Research progress on lung cancer stem cells in epidermal growth factor receptor–tyrosine kinase inhibitor targeted therapy resistance in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related deaths globally.In recent years,with the widespread use of genetic testing,epidermal growth factor receptor–tyrosine kinase inhibitor(EGFR-TKI)–targeted drugs have been efficacious to patients with lung adenocarcinoma exhibiting EGFR mutations.However,resistance to treatment is inevitable and eventually leads to tumor progression,recurrence,and reduction in the overall treatment efficacy.Lung cancer stem cells play a crucial role in the development of resistance toward EGFR-TKI–targeted therapy for lung adenocarcinoma.Lung cancer stem cells possess self-renewal,multilineage differentiation,and unlimited proliferation capabilities,which efficiently contribute to tumor formation and ultimately lead to tumor recurrence andmetastasis.In this study,we evaluated the origin,markers,stemness index,relevant classic studies,resistance mechanisms,related signaling pathways,and strategies for reversing lung cancer stem cell resistance to EGFR-TKIs to provide new insights on delaying or reducing resistance and to improve the treatment efficacy of patients with EGFR-mutated lung adenocarcinoma in the future.

Clinical relevance of stem cells in lung cancer

Lung cancer is the major cause of cancer-related deaths worldwide,it has one of the lowest 5-year survival rate,mainly because it is diagnosed in the late stage of the disease.Lung cancer is classified into two groups,small cell lung cancer(SCLC)and non-SCLC(NSCLC).In turn,NSCLC is categorized into three distinct cell subtypes:Adenocarcinoma,squamous cell carcinoma,and large cell carcinoma.NSCLC is the most common lung cancer,accounting for 85%of all lung cancers.Treatment for lung cancer is linked to the cell type and stage of the disease,involving chemotherapy,radiation therapy,and surgery.Despite improvements in therapeutic treatments,lung cancer patients show high rates of recurrence,metastasis,and resistance to chemotherapy.Lung stem cells(SCs)are undifferentiated cells capable of self-renewal and proliferation,are resistant to chemotherapy and radiotherapy and,due to their properties,could be involved in the development and progression of lung cancer.The presence of SCs in the lung tissue could be the reason why lung cancer is difficult to treat.The identification of lung cancer stem cells biomarkers is of interest for precision medicine using new therapeutic agents directed against these cell populations.In this review,we present the current knowledge on lung SCs and discuss their functional role in the initiation and progression of lung cancer,as well as their role in tumor resistance to chemotherapy.

The role of stem cells in airway repair:implications for the origins of lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide.Recently,advancements in our ability to identify and study stem cell populations in the lung have helped researchers to elucidate the central role that cells with stem cell-like properties may have in lung tumorigenesis.Much of this research has focused on the use of the airway repair model to study response to injury.In this review,we discuss the primary evidence of the role that cancer stem cells play in lung cancer development.The implications of a stem cell origin of lung cancer are reviewed,and the importance of ongoing research to identify novel therapeutic and prognostic targets is reiterated.

Potential of Hematopoietic Stem Cells and Mitotic Activity in Peripheral Lymphocytes to Predict Life Expectancy of Patients with Metastatic Non-Small Cell Lung Cancer after Conventional Therapy

To prevent potential overtreatment of metastatic non-small cell lung cancer, the individual parameters of circulating hematopoietic stem cells (HSCs) (percentage of CD133+ HSCs, CD34+ HSCs, and mitotic activity in the circulating lymphocyte fraction) were measured before conventional cytotoxic therapy in 35 patients by flow cytometry and then compared retrospectively with their individual survival periods. The plot of dependence of the CD133+ HSC × mitotic activity product versus CD34+ HSC revealed the prognostic properties during the survival period (range 0.3 - 124 months). Discrimination of patients with an expected survival shorter than 12 months was possible based on the positions of individual points on the plot, with a sensitivity and specificity of ∼100 each and a diagnostic odds ratio of 1250. The evaluation of individual lymphoproliferative resources before cytotoxic treatment may be useful for the optimal therapeutic compromise between the desired inhibition of malignant target cells and the life-threatening depression of lymphocytopoiesis.

Defining lung cancer stem cells exosomal payload of miRNAs in clinical perspective

Since the first publication regarding the existence of stem cells in cancer[cancer stem cells(CSCs)]in 1994,many studies have been published providing in-depth information about their biology and function.This research has paved the way in terms of appreciating the role of CSCs in tumour aggressiveness,progression,recurrence and resistance to cancer therapy.Targeting CSCs for cancer therapy has still not progressed to a sufficient degree,particularly in terms of exploring the mechanism of dynamic interconversion between CSCs and non-CSCs.Besides the CSC scenario,the problem of cancer dissemination has been analyzed indepth with the identification and isolation of microRNAs(miRs),which are now considered to be compelling molecular markers in the diagnosis and prognosis of tumours in general and specifically in patients with non-small cell lung cancer.Paracrine release of miRs via“exosomes”(small membrane vesicles(30-100 nm),the derivation of which lies in the luminal membranes of multi-vesicular bodies)released by fusion with the cell membrane is gaining popularity.Whether exosomes play a significant role in maintaining a dynamic equilibrium state between CSCs and non-CSCs and their mechanism of activity is as yet unknown.Future studies on CSC-related exosomes will provide new perspectives for precision-targeted treatment strategies.

Roles of nitric oxide on cancer stemness and metastasis in lung cancer cells

The cancer microenvironment has been reported to have a significant impact on cancer cells in many ways.Indeed,in such an active environment,cell signaling molecules as well as mediators including proinflammatory cytokines and reactive species are found to be intensified.Among them,the concentrations of nitric oxide(NO),a reactive nitrogen species synthesized by many cells,such as endothelial,immune,and tumor cells,are found to be dramatically increased in lung cancer environments[1].Additionally,clinical observation has shown that NO levels in the lungs of lung cancer patients were increased in comparison to those of normal subjects[2].Together,these studies strongly support the role of NO in tumorigenesis and metastasis,although the underlying mechanisms remain obscure.

Inhibition of lung cancer stem cells self-renewal and tumorigenicity by lentivirus-delivered Bmi1 shRNA

Objective： The aim of the study was to observe the effect of Bmil reduction on the self-renewal and tumorigenicity ability of lung cancer stem cells （LCSCs） in human lung adenocarcinoma. Methods： Human lung adenocarcinoma cells A549 were consecutively passaged in NOD/SCID mice treated with Paclitaxel weekly. The proportions of LCSCs in A549 cells and the cells from the third passage （A549-3rd） were compared. The expression of Bmil in LCSCs was silenced by intratumoral injection with lentivirus-delivered Broil small hairpin RNA （shRNA）. RT-PCR and Western blot were used to test the mRNA and protein expressions of Broil in LCSCs. The protein level of p16INK4A was analyzed by Western blotting. The self- renewal and tumorigenicity ability of LCSCs were evaluated by counting the sphere formation rate in serum-free medium and the tumor formation rate in NOD/SCID mice. Results： In vivo passaging ofA549 cells under chemotherapy pressure enriched for LCSCs. The expression of Broil in LCSCs increased. Down-regulation of Bmil by RNA interference resulted in reduced self-renewal and tumorigenicity ability of LCSCs and paralleled the increased expression of p16INK4A, a Bmil target. Conclu- sion： Broil regulates self-renewal and tumorigenicity of LCSCs by silencing some target genes, including p16INK4A.

The related effects of astragalus polysaccharides on the improvement of bone marrow suppression and hematopoietic stem cells during chemotherapy in elderly patients with lung cancer

Objective:To investigate the effects of astragalus polysaccharides(APS)on bone marrow suppression and hematopoietic stem cells during chemotherapy in elderly patients with lung cancer.Methods:120 elderly patients with lung cancer treated in the first hospital of Xingtai city from January 2019 to early December 2019 were divided into the treatment group and the control group by the random number table method,all of whom received pemetrexed+carboplatin chemotherapy,and the treatment group was treated with APS at the same time.The efficacy was evaluated after 2 cycles of chemotherapy,bone marrow suppression was observed,and levels of TCM symptoms score,peripheral blood T lymphocyte subgroup index,L-selectin(CD62L)and macrophage differentiation antigen-1(Mac-1)were measured before and after 2 cycles of chemotherapy.Results:The response rate(RR)was 56.67%in the treatment group and 45.00%in the control group,with no statistically significant difference(P>0.05);The disease control rate(DCR)in the treatment group was 81.67%,which was significantly higher than 65.00%in the control group(P<0.05);The reduction degree of leukopenia in the treatment group was significantly lower than that in the control group(P<0.05);The treatment group had a platelet reduction of grade 1+2 at a rate of 40.00%,and hemoglobin reduction of grade 1+2 at a rate of 28.33%,which were significantly lower than the control group at 65.00%and 58.33%(P<0.05);Compared with those before chemotherapy,the total score of TCM symptoms,serum CD62L and Mac-1 levels in the two groups all decreased significantly after chemotherapy,and they were significantly lower in the treatment group than in the control group(P<0.05);After chemotherapy,CD3+,CD4+and CD4+/CD8+in the treatment group increased significantly and they were all higher in the treatment group than in the control group,while CD8+decreased significantly and was lower in the treatment group than in the control group(P<0.05).There was no statistically significant difference in T lymphocyte subsets before and after chemotherapy in the control group(P>0.05).Conclusion:Astragalus polysaccharide can improve the chemotherapy effect and improve the bone marrow suppression in elderly patients with lung cancer,which may be related to its obvious enhancement of immune function and decrease of CD62L and Mac-1 levels.

Embryonic stem cells against non-small cell lung cancer in vivo

Objective To investigate the function and mechanism of embryonic stem cells again Lewis non-small cell lung cancer in vivo. Methods Based on the mouse Lewis non-small cell lung cancer model,we have tested some tumor growth indexes and investigated the immune response of embryonic stem cells against cancer cells. Results Compared with the mice in control group,mice

Game-changing insights on vertebral skeletal stem cells in bone metastasis and therapeutic horizons

Greenblatt and his team have unveiled vertebral skeletal stem cells(vSSCs)as a critical player in the landscape of bone metastasis.This commentary delves into the transformative discoveries surrounding vSSCs,emphasizing their distinct role in bone metastasis compared to other stem cell lineages.We illuminate the unique properties and functions of vSSCs,which may account for the elevated susceptibility of vertebral bones to metastatic invasion.Furthermore,we explore the exciting therapeutic horizons opened by this newfound understanding.These include potential interventions targeting vSSCs,modulation of associated signaling pathways,and broader implications for the treatment and management of bone metastasis.By shedding light on these game-changing insights,we hope to pave the way for novel strategies that could revolutionize the prognosis and treatment landscape for cancer patients with metastatic bone disease.

Knockdown of circular RNA (CircRNA)_001896 inhibits cervical cancer proliferation and stemness in vivo and in vitro

Objective:Previous studies indicated that aberrant circular RNA(circRNA)expression affects gene expression regulatory networks,leading to the aberrant activation of tumor pathways and promoting tumor cell growth.However,the expression,clinical significance,and effects on cell propagation,invasion,and dissemination of circRNA_001896 in cervical cancer(CC)tissues remain unclear.Methods:The Gene Expression Omnibus(GEO)datasets(GSE113696 and GSE102686)were used to examine differential circRNA expression in CC and adjacent tissues.The expression of circRNA_001896 was detected in 72 CC patients usingfluorescence quantitative PCR.Correlation analysis with clinical pathological features was performed through COX multivariate and univariate analysis.The effect of circRNA_001896 downregulation on CC cell propagation was examined using the cell counting kit-8(CCK-8)test,clonogenic,3D sphere formation,and in vivo tumorigenesis assays.Results:Intersection of the GSE113696 and GSE102686 datasets revealed an increased expression of four circRNAs,including circRNA_001896,in CC tissues.Fluorescence quantitative PCR confirmed circRNA_001896 as a circular RNA.High expression of circRNA_001896 was considerably associated with lymph node metastasis,International Federation of Gynecologists and Obstetricians(FIGO)stage,tumor diameter,and survival period in CC patients.Proportional hazards model(COX)univariate and multivariate analyses revealed that circRNA_001896 expressions are a distinct risk factor affecting CC patients’prognosis.Cellular functional experiments showed that downregulating circRNA_001896 substantially suppressed CC cell growth,colony formation,and 3D sphere-forming ability.In vivo,tumorigenesis analysis in nude mice demonstrated that downregulating circRNA_001896 remarkably reduced the in vivo proliferation capacity of CC cells.Conclusion:CircRNA_001896 is highly expressed in CC tissues and is substantially related to lymph node metastasis,FIGO stage,tumor size,and survival period in patients.Moreover,downregulating circRNA_001896 significantly inhibits both in vivo and in vitro propagation of CC cells.Therefore,circRNA_001896 might be used as a biomarker for targeted therapy in cervical cancer.

An inhibitor of HIF-α subunit expression suppresses hypoxiainduced dedifferentiation of human NSCLC into cancer stem cell-like cells

AIM:To investigate whether hypoxia induces dedifferentiation of non-small cell lung cancer(NSCLC) cells and whether a hypoxia-inducible factor(HIF) inhibitor is able to suppress the process.METHODS:Human lung adenocarcinoma A549 cells and squamous carcinoma QG56 cells were cultured under normoxic(21%O_2) or hypoxic(4%or 1%O_2) conditions.The expression of the following genes were examined by reverse transcription-polymerase chain reaction,Western blotting and/or immunofluorescence:HIF-1α and HIF-2αsubunits;differentiation marker genes,namely surfactant protein C(SP-C)(type Ⅱ alveolar cell marker),CC10(type I alveolar cell marker) and aquaporin 5(AQP5)(Clara cell marker);and stem cell-associated genes,namely CD133,0CT4,and Musashi-1(MSI1).The tumor sphere-forming ability of the cells was evaluated by culturing them in serum-free growth factor-rich medium containing epidermal growth factor(EGF) and fibroblast growth factor(FGF).CD133 expression in hypoxic regions in A549 tumors was examined by double-immunostaining of tissue cryosections with an anti-2-nitroimidazole EF5 antibody and an anti-CD133 antibody.The metastatic ability of A549 cells was examined macroscopically and histologically after injecting them into the tail vein of immunocompromised mice.RESULTS:A549 cells primarily expressed SP-C,and QG56 cells expressed CC10 and AQP5.Exposure of A549 cells to hypoxia resulted in a marked downregulation of SP-C and upregulation of CD133,OCT4,and MSI1 in a time-dependent manner.Moreover,hypoxia mimetics,namely desferrioxamine and cobalt chloride,elicited similar effects.Ectopic expression of the constitutively active HIF-la subunit also caused the downregulation of SP-C and upregulation of CD133 and MSI1 but not OCT4,which is a direct target of HIF-2.Hypoxia enhanced the sphere-forming activity of A549 cells in serum-free medium containing EGF and FGF.Similarly,hypoxia downregulated the expression of CC10 and AQP5 genes and upregulated CD133,OCT4,and MSI1 genes in QG56 cells.TX-402(3-amino-2-quinoxalinecarbonitrile 1,4-dioxide),which is a small molecule inhibitor of the expression of HIF-1α and HIF-2αsubunits under hypoxic conditions,inhibited the upregulation of SP-C'and hypoxia-induced down-regulation of CD133,OCT4,and MSI1.Notably,TX-402 significantly suppressed the hypoxia-enhanced lung-colonizing ability of A549 cells.CONCLUSION:Hypoxia induces the de-differentiation of NSCLC cells into cancer stem cell-like cells,and HIF inhibitors are promising agents to prevent this process.

Clinical Course Of Patients with Small Cell Lung Cancer As Second Primary Malignancy

Objective： To evaluate the clinical course of patients with small cell lung cancer （SCLC） as second primary malignancy. Methods： Among the 355 patients diagnosed with SCLC at Helen and Harry Gray Cancer Center of Hartford Hospital Connecticut USA between 1988 and 1998, the records of 48 patients, which had been diagnosed with other malignancies before their diagnosis of SCLC, were retro- spectively reviewed. Results： Forty-eight patients （13.5%） were diagnosed with other malignancies prior to their SCLC among which 43 had documented smoking history and 93% of them （40/43） were current/former smokers. Of the 28-second primary SCLC patients who were treated with standard method, 11 （39.3%） achieved CR. 12 （42.8%） achieved PR, and the RR was 82.1%. The median survival of the 28 treated with standard method was 11.3 months （5.1-77.7 months）, while that of the rest 19 untreated patients （1 of 20 was lost to follow-up） was only 2.0 months （0.5 34.0 months）. There was no significant difference in the median survival and RR between 165 treated first primary SCLC （13.5 months and 77.6% respectively） and 28 treated secondary primary SCLC （11.3 months and 82.1% respectively） （P〉0.05）. The patients who had prostate cancer were older and subjected to less treatments than those with skin cancer, so their survival was shorter than the latter （3.5 months vs. 15 months, P〈0.05）. Conclusion： The response and survival of the treated patients with SCLC as a second malignancy showed no difference as compared to the treated ones with SCLC only. Therefore, an active medical treatment is important to relieve symptom and prolong survival of the second primary SCLC patients.

DIAGNOSTIC VALUE OF SERUM PROGRP31-98 IN PATIENTS WITH SMALL-CELL LUNG CANCER

Objective To explore the clinical significance of serum level of pro gastrin releasing peptide 31 98 (ProGRP31 98) for small cell lung cancer (SCLC), in comparison with neuron specific enolase (NSE). Methods Serum level of ProGRP31 98 and NSE was measured by ELISA respectively in 30 patients with SCLC, 30 with non small cell lung cancer (NSCLC), 15 with benign lung diseases and 15 normal subjects, additionally, 10 SCLC patients after having treatment with chemotherapy were included. The receiver operating characteristic (ROC) curve was used to set the cut off value and evaluate the diagnostic accuracy. Results The serum level of ProGRP31 98 was higher in patients with SCLC than that in other groups. The SCLC patients with extensive disease had a higher value than the patients with limited disease. In SCLC patients with distant metastases, it was also higher than in those without. Increase in serum ProGRP31 98 and NSE was both seen in SCLC patients, but for the former one, the increase was of much greater compared to the normal controls. Given the cut off value for ProGRP31 98 was 40ng·L -1 and for NSE 8μg·L -1 , their sensitivity of diagnosis in SCLC was 73% and 60%, respectively. The area under ROC curve of ProGRP31 98 was significantly larger than that of NSE. All patients responded to chemotherapy showed marked decrease in ProGRP31 98. Conclusion ProGRP31 98 is a more specific and sensitive marker than NSE in the diagnosis of SCLC.

PGRMC1 Elevation in Multiple Cancers and Essential Role in Stem Cell Survival

Cancer is one of the leading causes of death in America, and there is an urgent need for new therapeutic approaches. The progesterone receptor membrane component 1 (PGRMC1) is a cytochrome b5 related protein that binds heme and is associated with signaling, apoptotic suppression and autophagy. PGRMC1 is essential for tumor formation, invasion and metastasis, and is upregulated in breast, colon, lung and thyroid tumors. In the present study, we have analyzed PGRMC1 levels in over 600 tumor sections, including a larger cohort of lung tumors than in previous studies, and report the first clinical analysis of PGRMC1 levels in human oral cavity and ovarian tumors compared to corresponding nonmalignant tissues. PGRMC1 was highly expressed in lung and ovarian cancers and correlated with patient survival. PGRMC1 has been previously associated with drug resistance, a characteristic of cancer stem cells. The stem cell theory proposes that a subset of cancerous stem cells contribute to drug resistance and tumor maintenance, and PGRMC1 was detected in lung-tumor derived stem cells. Drug treatment with a PGRMC1 inhibitor, AG-205, triggered stem cell death whereas treatment with erlotinib and the ERK inhibitor, PD98059, did not, suggesting a specific role for PGRMC1 in cancer stem cell viability. Together, our data demonstrate PGRMC1 as a potential tumor biomarker across a variety of tumors, as well as a therapeutic target for cancer stem cells.

HYPERMETHYLATION OF p14^(ARF) PROMOTER REGION AND EXPRESION OF p14^(ARF) GENE PRODUCT IN NON-SMALL CELL LUNG CANCER

Objective： This study was designed to investigate promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer, and value the role of p14^ARF promoter methylation in carcinogenesis of non-small cell lung cancer. Methods： Promoter methylation status and protein expression of p14^ARF gene in 40 cases of non-small cell lung cancer were analyzed by methylation specific polymerase china reaction （MSP）, restriction enzyme-related polymerase chain reaction （RE-PCR） and immunohistochemistry （IHC）. Results： The positive rates of p14^ARF promoter methylation in tumor tissues and normal tissues adjacent to cancer were 17.5% （7/40） and 2.5% （1/40） respectively. There were statistically significant differences between them, P〈0.05. The results of RE-PCR were consistent with that of MSP. The expression rate of p14^ARF protein in tumor tissues was significantly lower than that in normal tissues adjacent to cancer, p〈0.01. Promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer showed significantly an inverse correlation （r=-0.56, P〈0.01）, and both of them did not relate statistically with the clinicopathologic characteristics of patients such as histological classification, clinical stage, differentiation grade and lymph node involvement. Conclusion： Promoter methylation is a crucial mechanism of inactivation of p14^ARF gene. Promoter methylation of p14^ARF gene might he involved in carcinogenesis of non-small cell lung cancer, and is an early event in development process of non-small cell lung cancer. It might be used as a new target in gene treatments in the future.

Stem cell biology in thyroid cancer: Insights for novel therapies

Currently, thyroid cancer is one of the most common endocrine cancer in the United States. A recent involvement of sub-population of stem cells, cancer stem cells, has been proposed in different histological types of thyroid cancer. Because of their ability of self-renewal and differentiation into various specialized cells in the body, these putative cells drive tumor genesis, metastatic activity and are responsible to provide chemo- and radioresistant nature to the cancer cells in the thyroid gland. Our Review was conducted from previously published literature to provide latest apprises to investigate the role of embryonic, somatic and cancer stem cells, and discusses the hypothesis of epithelial-mesenchymal transition. Different methods for their identification and isolation through stemness markers using various in vivo and in vitro methods such as flow cytometry, thyrosphere formation assay, aldehyde dehydrogenase activity and ATP-binding cassette sub-family G member 2 efflux-pump mediated Hoechst 33342 dye exclusion have been discussed. The review also outlines various setbacks that still remain to target these tumor initiating cells. Future perspectives of therapeutic strategies and their potential to treat advanced stages of thyroid cancer are also disclosed in this review.

Therapy-related myeloid leukemia during erlotinib treatment in a non-small cell lung cancer patient:A case report

BACKGROUND Epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs)are tolerable drugs used for patients with EGFR-mutant advanced non-small cell lung cancer(NSCLC).Serious adverse reactions are uncommon compared with cytotoxic drugs.CASE SUMMARY A 52-year-old man presented with general weakness and cytopenia.He had been taking erlotinib for 11 mo to treat NSCLC.The pathological diagnosis from the right upper lobe mass was adenocarcinoma with an EGFR mutation in exon 21(L858R).He had previously received paclitaxel/carboplatin,gemcitabin/vinorelbine chemotherapy,stereotactic radiosurgery for brain metastasis,and whole-brain radiotherapy as treatment for NSCLC.We diagnosed the patient with acute myeloid leukemia(AML).During the induction and consolidation chemotherapy for AML,the erlotinib was discontinued.When complete remission of the AML was achieved,since the lung masses were increased,pemetrexed/cisplatin for the NSCLC was initiated.After two cycles of chemotherapy,the cytopenia was prolonged.AML relapse occurred with the same karyotype.CONCLUSION Therapy-related acute myeloid neoplasm(t-MN)is a rare but fatal late complication.Although a patient may be taking EGFR-TKIs,the possibility of t-MN should be considered.Further studies are needed to determine whether EGFR-TKI usage is a predisposing factor for t-MN.

Targeting head and neck tumoral stem cells： From biologicalaspects to therapeutic perspectives

Head and neck squamous cell cancer(HNSCC) is the sixth most common cancer in the world. Effective therapeutic modalities such as surgery, radiation, chemotherapy and combinations of each are used in the management of the disease. In most cases, treatment fails to obtain total cancer cure. In recent years, it appears that one of the key determinants of treatment failure may be the presence of cancer stem cells(CSCs) that escape currently available therapies. CSCs form a small portion of the total tumor burden but may play a disproportionately important role in determining outcomes. CSCs have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. A large body of evidence points to the fact that CSCs are particularly resistant to radiotherapy and chemotherapy. In HNSCC, CSCs have been increasingly shown to have an integral role in tumor initiation, disease progression, metastasis and treatment resistance. In the light of such observations, the present review summarizes biological characteristics of CSCs in HNSCC, outlines targeted strategies for the successful eradication of CSCs in HNSCC including targeting the self-renewal controlling pathways, blocking epithelial mesenchymal transition, niche targeting, immunotherapy approaches and highlights the need to better understand CSCs biology for new treatments modalities.

Role of positron emission tomography-computed tomography in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell carcinoma and small cell carcinoma are the main histological subtypes and constitutes around 85% and 15% of all lung cancer respectively. Multimodality treatment plays a key role in the successful management of lung cancer depending upon the histological subtype, stage of disease, and performance status. Imaging modalities play an important role in the diagnosis and accurate staging of the disease, in assessing the response to neoadjuvant therapy, and in the follow-up of the patients. Last decade has witnessed voluminous upsurge in the use of positron emission tomography-computed tomography(PET-CT); role of PET-CT has widened exponentially in the management of lung cancer. The present article reviews the role of 18-fluoro-deoxyglucose PET-CT in the management of non small cell lung cancer with emphasis on staging of the disease and the assessment of response to neoadjuvant therapy based on available literature.