Genetic aberration in primary hepatocellular carcinoma:correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23

To elucidate the molecular pathology underlying the development of hepatocellular carcinoma (HCC), we used 41 highly polymorphic microsatellite markers to examine 55 HCC and corresponding non-tumor liver tissues on chromosome 9, 16 and 17. Loss-of-heterozygosity (LOH) is observed with high frequency on chromosomal region 17p13 (36/55, 65%), 9p21-p23 (28/55, 51%), 16q21-q23 (27/55, 49%) in tumors. Meanwhile, microsatellite instability is rarely found in these microsatellite loci. Direct sequencing was performed to detect the tentative mutation of tumor suppressor genes in these regions: p53, MTS1/p16, and CDH1/E-cadherin. Within exon 5-9 of p53 gene, 14 out of 55 HCC specimens (24%) have somatic mutations, and nucleotide deletion of this gene is reported in HCC for the first time. Mutation in MTS1/pl6 is found only in one tumor case. We do not find mutations in CDH1/E-cadherin. Furthermore, a statistically significant correlation is present between p53 gene mutation and loss of chromosome region 16q21q23 and 9p21-p23, which indicates that synergism between p53 inactivation and deletion of 16q21-q23 and 9p21-p23 may play a role in the pathogenesis of HCC. Genetic aberration in hepatocellular

Screen p53 mutations in hepatocellular carcinoma by FASAY:A novel splicing mutation

Objective： To establish a routine procedure for the detection of p53 mutations in hepatocellular carcinoma （HCC） surgical resections using the FASAY （functional analysis of separated alleles of p53 on yeast） procedure. Methods： p53 status was analyzed by FASAY and cDNA sequencing in 50 cases of HCC. After the extraction of RNA from the frozen tumor and corresponding normal tissues, reverse transcription RT-PCR was carried out using these samples. The assay can detect mutations of p53 mRNA between codons 67 and 347 by the DNA-binding activity of the protein and reveal them as red colonies. Results： Of the 50 specimens, 29 （58%） were positive （mutan0 by FASAY. Sequencing analysis confirmed that all 29 FASAY positive tumors harbored mutations, and that no mutations were detectable in any FASAY negative tumors. In 29 p53 mutations, 22 mutations were point missense mutation, 5 were deletions and 2 were splicing mutations. A novel splice mutation on splice donor of intron 6 was reported, which could produce two different mRNAs, respectively using the nearest upstream and downstream recessive splice donor sites. Conclusion： FASAY is a sensitive method for detecting the various types of p53 mutations in HCC, suggesting that the yeast functional assay for the detection of p53 mutations may be essential for elucidating their clinical significance.

P53 GENE MUTATIONS IN NON-SMALL CELL LUNG CANCER DETECTED BY POLYMERASE CHAIN REACTION SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS

Mutations of the p53 tumor suppressor gene are the most frequent genetic alterations detected in human lung cancer. To assess the pathogenic significance of p53 gene alterations in Chinese non small cell lung cancer(NSCLC),74 paired samples of primary lung cancer and normal lung tissue far away from the cancer were analyzed for mutations of the p53 gene(exons 5 8) using exon specific PCR, single strand conformation polymorphism (PCR SSCP). p53 mutations were observed in 55 4%(41/74) of the samples. No linkages were detected between the incidence of p53 mutations and histological type, lymph node metastasis,age or sex. Significant association between p53 mutations and degree of differentiation in adenocarcinomas, not in squamous cell carcinomas, was observed. The frequency of p53 mutations in smokers(65 3%) was higher than in nonsmokers(33 3%) and reached statistical significance.We also found p53 mutations in 6/7 samples which had tissue invasion and distant metastasis.These results suggest that smoking could be an important factor in lung carcinogenesis,p53 mutation is a worse prognosis indicator in adenocarcinomas and related to high aggressive behavior of human lung cancer.

Analysis of P53 Mutation and Invasion Front Grading in Oral Squamous Cell Carcinomas

We examined P53 mutation and invasion front grading (IFG) in 30 cases of oral squamous cell carcinomas (OSCCs). The association of P53 mutation and IFG scores with clinicopa-thological parameters was evaluated. P53 mutation existed in exon 5-8 in 15 out of the 30 OSCCs (50%). The incidence of P53 mutation was not associated with age, gender, N value and TNM stage. However, there was a significant correlation between P53 mutation and T value (P=0.046). There were no statistically significant correlations among the clinicopathological parameters and IFG. Interestingly, The IFG score in OSCCs with P53 mutation was significantly higher than that in OSCCs without P53 mutation (P<0.001). These results suggest that the high incidence of P53 mutation is a major mechanism of OSCC carcinogenesis. The presence of P53 mutation indicates the most anaplastic fields in the invasive areas of the tumors, which may predict poor prognosis for the patients.

p53 Gene Mutations in Asbestos Associated Cancers

The accumulation of mutant p53 protein in cancer cells was observed by immunohistochemistry analysis. DNA was extracted from paraffin-embedded tissue. Exons 5, 7 and 8 were amplified and studied by PCR-SSCP and sequencing analysis. Ten cases of asbestos associated cancer tissue were studied, of which five cases had adenocarcinoma, and the other five had mesothelioma, squamous carcinoma, small cell lung cancerl adenosquamous carcinoma and malignant lymphoma respectively. Employing monoclonal antibody PAb1801, five cases were found to be mutant p53 protein mpitive. Seven cases were found to have mutations by PCRSSCP. A total of 7 cases (8 mutations) were found to be positive and 4 cases were found to be opitive by both of these analyses. Of the 8 mutations found by SSCP analysis, 4(50%, 4/8)were clustered in exon 8. A high mutation frequency was noticed in adenocarcinoma (80%,4/5). ffequencing analysis on two specimens revealed two hotspot mutations. In codon 234,TAC for tyrooin was mutated to AAC fOr aspar8gine by a T to A transversion of the first letter. In codon 273, CGT for arginine was mutated to AGT for serine by a C to A transversion of the first letter. ln conclusion, the mutation of p53 gene is common in asbestos associated cancers. However, the mutational spectrum of asbestos associated cancers might be different from that of non-asbestos associated cancers.

P53 Gene Mutations in Non-Hodgkin's Lymphoma

Summary: To understand P53 gene change of non Hodgkin's lymphoma (NHL) and human malignant lymphoma cell lines, the exons 5 7 of 29 patients with NHL and 9 kinds of human malignant lymphoma cell lines were studied by silver staining PCR SSCP technique. Three cases of P53 gene point mutation was found in 29 cases of NHL. Mutation developed in exon 5 in 2 cases, and in exon 6 in 1 case. They were all diffuse lymphoma. In mutation cases, B cell lymphoma accounted for 2 cases and the other one was T cell lymphoma. There was no P53 gene mutation in low grade follicular lymphoma. Seven strains out of 9 kinds of lymphoma cell lines had P53 gene point mutation. One strain had the mutation in exon 5; 5 strains in exon 6 and 1 strain in exons 5, 6, 7. There was a high mutation rate in lymphoma cell lines and low mutation rate in NHL patients. P53 gene plays an important role in lymphoma cell line establishment, cell regeneration and disease evolution.

Abnormal Change of p53 Gene in Gastric and PrecancerousLesions and APC Gene Deletion in Gastric Carcinoma and Near Tissues

p53 gene mutation (exon4, 5, 6, 7, 8 and intron6) in gastric cancer and precancerous lesions and p53 gene (exon4 and ontron6), APC gene deletion in gastric carcinomas were studied by PCR/SSCP and PCR/RFLP- Results showed mutation rate of p53 in metaplasia, dysplasia and gastric carcinoma was 37. 5 % (3/8), 42. 11 % (8/19), 53. 33 (16/30) respectively- There was significant dif-ference among groups of metaplasia, dysplasia, cancer and normal controls. Noexon8 mutation was found in metaplasia and dysplasia, but 4 cases were found to have exon8 mutation in cancer group. It is suggested that exon8 mutation occurs at the late stage of gastric cancer, but exon 5, 6, 7 mutation occur in the course ofprecancerous lesion to cancer. Loss of heterozygosity (LOH) of exon4, intron6,APC was 47,37 % (9/19), 8. 73% (2/23), 16. 67 % (3/18) respectively. LOH of exon4 had something to do with poor differentiation, lymph node metastasis,depth of invasion- LOH of exon4 may be one of prognostic marker of gastric cancer. We are led to conclude that p53 gene mutation is an early event and perhaps work together with ras oncogene in gastric carcinogenesis

Helicobacter pylori and gastric cancer: Indian enigma

Helicobacter pylori (H. pylori) is a gram negative microaerophilic bacterium which resides in the mucous linings of the stomach. It has been implicated in the causation of various gastric disorders including gastric cancer. The geographical distribution and etiology of gastric cancer differ widely in different geographical regions and H. pylori, despite being labeled as a grade&#x02005;I&#x02005;carcinogen, has not been found to be associated with gastric cancer in many areas. Studies in Asian countries such as Thailand, India, Bangladesh, Pakistan, Iran, Saudi Arabian countries, Israel and Malaysia, have reported a high frequency of H. pylori infection co-existing with a low incidence of gastric cancer. In India, a difference in the prevalence of H. pylori infection and gastric cancer has been noted even in different regions of the country leading to a puzzle when attempting to find the causes of these variations. This puzzle of H. pylori distribution and gastric cancer epidemiology is known as the Indian enigma. In this review we have attempted to explain the Indian enigma using evidence from various Indian studies and from around the globe. This review covers aspects of epidemiology, the various biological strains present in different parts of the country and within individuals, the status of different H. pylori-related diseases and the molecular pathogenesis of the bacterium.

Clinicopathology, immunophenotype, T cell receptor gene rearrangement, Epstein-Barr virus status andp53 gene mutation of cutaneous extranodal NK/T-cell lymphoma, nasal-type

Background Extranodal natural killer/T-cell （NK/T cell） lymphoma, nasal-type, is a rare lymphoma. Skin is the second most common site of involvement after the nasal cavity/nasalpharynx. The aim of this study was to investigate the clinicopathologic features, immunophenotype, T cell receptor （TCR） gene rearrangement, the association with Epstein-Barr virus （EBV） infection and p53 gene mutations of the lymphoma. Methods The clinicopathologic analysis, immunohistochemistry, in situ hybridization for EBERI/2, TCR gene rearrangement by polymerase chain reaction （PCR）, mutations of p53 gene analyzed by PCR and sequence analysis were employed in this study. Results In the 19 cases, the tumor primarily involved the dermis and subcutaneous layer. Immunohistochemical staining showed that most of the cases expressed CD45RO, CD56, CD3E, TIA-1 and GrB. Three cases were positive for CD3 and two cases were positive for CD30. Monoclonal TCRy gene rearrangement was found in 7 of 18 cases. The positive rate of EBERI/2 was 100%. No p53 gene mutation was detected on the exon 4-9 in the 18 cases. Fifteen cases showed Pro （proline）/Arg （arginine） single nucleotide polymorphisms （SNPs） on the exon 4 at codon 72. The expression of p53 protein was 72% （13/18）immunohistochemically. Conclusions Cutaneous NK/T-cell lymphoma is a rare but highly aggressive lymphoma with poor prognosis. No p53 gene mutation was detected on the exon 4-9, and Pro/Arg SNPs on p53 codon 72 were detected in the cutaneous NK/T-cell lymphoma. The overexpression of p53 protein may not be the result of p53 gene mutation.

Evaluation of Intraductal Ultrasonography, Endoscopic Brush Cytology and K-ras, P53 Gene Mutation in the Early Diagnosis of Malignant Bile Duct Stricture

Background： In qualitative diagnosis of bile duct stenosis, single diagnostic measure is difficult to make a correct diagnosis, to combine several diagnostic techniques may be helpful to make an accurate diagnosis. The aim of this study was to evaluate the value of intraductal ultrasonography （IDUS）, endoscopic brush cytology and K-ras, P53 gene mutation in the early diagnosis of malignant biliary stricture. Methods： From February 2012 to February 2013, 84 patients with suspected malignant biliary stricture were performed I DUS firstly, then endoscopic brush cytology and finally K-ras, P53 gene mutation detection, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of all above ways were evaluated and compared. Results： Of 84 patients, 52 cases were ultimately diagnosed malignant biliary stenosis; of which, 9 cases had no recurrence or metastasis to other organs after radical operation during the follow-up period. IDUS combined with brush cytology and K-ras ＋ P53 gene mutation detection had obvious advantage in the sensitivity, accuracy and negative predictive value than any other joint detection and single detection （the advantage was more significant compared with IDUS ＋ brush cytology or any single detection P 〈 0.01）. There were obvious statistical significance in the sensitivity and accuracy between IDUS ＋ brush cytology ＋ P53 or IDUS ＋ brush cytology ＋ K-ras and IDUS ＋ brush cytology or IDUS （P 〈 0.05）. There was no statistical significance in the sensitivity, specificity, positive predictive value, negative predictive value and accuracy between IDUS ＋ brush cytology ＋ P53 and IDUS ＋ brush cytology ＋ K-ras （P 〉 0.05）. Conclusions： IDUS combined with brush cytology and K-ras, P53 gene mutation detection is better than the separate detection and contribute to the early diagnosis of malignant biliary stricture. Its more widespread use is recommended.

Detection of p53 gene mutations in skeletal muscle cell of patients with chronic heart failure

Progressive deterioration of physical work capacity in congestive heart failure (CHF) is often attributed to ongoing skeletal muscle atrophy and abnormalities in muscle metabolism. The purpose of the present study was to investigate if mutations in the p53 gene thought to be a promotor of apoptosis are involved in intrinsic apoptotic abnormalities in skeletal muscle of patients (pts) with CHF. Percutaneous needle biopsy from the m. vastus lateralis were obtained from 19 pts with CHF (LV EF 25%±10%). Single strand confirmation polymorphism analysis of polymerase chain reation products (PCR SSCP analysis) was used for detection of mutations in exon 5 8 of the p53 gene in skeletal Heart Center, University Leipzig, Germany (Yu JT, Adams V, Fiehn E, Schuler G and Hambrecht R) Institut of Pathology, University Freiburg, Germany (Ye J and Riede U)muscle cells. Four of 19 muscle specimens (21%) showed mobility shifts. To characterize the nuleotide sequence alterations specimens were examined further by direct sequence analysis of PCR product. Two of four specimens showing a band shift in the SSCP analysis exhibited a mutated p53 sequence. Sequence analysis revealed that these alteratons were point mutation exon 8 (14482, G→A) and deletion in exon 5 (13143 13157). A high frequency of p53 mutations was detected in skeletal muscle cells of patients with chronic heart failure. These findings suggest a role for apoptosis in the progression of intrinsic skeletal muscle abnormalities and consequently of exercise intolerance in chronic heart failure.

Twenty years of Gendicine?rAd-p53 cancer gene therapy:The first-in-class human cancer gene therapy in the era of personalized oncology

Genetic mutations in TP53 contribute to human malignancies through various means.To date,there have been a variety of therapeutic strategies targeting p53,including gene therapy to restore normal p53 function,mutant p53 rescue,inhibiting the MDM2-p53 interaction,p53-based vaccines,and a number of other approaches.This review focuses on the functions of TP53 and discusses the aberrant roles of mutant p53 in various types of cancer.Recombinant human p53 adenovirus,trademarked as Gendicine,which is the first anti-tumor gene therapy drug,has made tremendous progress in cancer gene therapy.We herein discuss the biological mechanisms by which Gendicine exerts its effects and describe the clinical re-sponses reported in clinical trials.Notably,the clinical studies suggest that the combination of Gendicine with chemotherapy and/or radiotherapy may produce more pronounced efficacy in slowing tumor growth and progression than gene therapy/chemotherapy alone.Finally,we summarize the methods of administration of recombinant human p53 adenovirus for different cancer types to provide a reference for future clinical trials.

Decitabine induces IRF7-mediated immune responses in p53-mutated triple-negative breast cancer:a clinical and translational study

p53 is mutated in half of cancer cases.However,no p53-targeting drugs have been approved.Here,we reposition decitabine for triple-negative breast cancer(TNBC),a subtype with frequent p53 mutations and extremely poor prognosis.In a retrospective study on tissue microarrays with 132 TNBC cases,DNMT1 overexpression was associated with p53 mutations(P=0.037)and poor overall survival(OS)(P=0.010).In a prospective DEciTabinE and Carboplatin in TNBC(DETECT)trial(NCT03295552),decitabine with carboplatin produced an objective response rate(ORR)of 42%in 12 patients with stage IV TNBC.Among the 9 trialed patients with available TP53 sequencing results,the 6 patients with p53 mutations had higher ORR(3/6 vs.0/3)and better OS(16.0 vs.4.0 months)than the patients with wild-type p53.In a mechanistic study,isogenic TNBC cell lines harboring DETECT-derived p53 mutations exhibited higher DNMT1 expression and decitabine sensitivity than the cell line with wild-type p53.In the DETECT trial,decitabine induced strong immune responses featuring the striking upregulation of the innate immune player IRF7 in the p53-mutated TNBC cell line(upregulation by 16-fold)and the most responsive patient with TNBC.Our integrative studies reveal the potential of repurposing decitabine for the treatment of p53-mutated TNBC and suggest IRF7 as a potential biomarker for decitabine-based treatments.

Novel p53 therapies for head and neck cancer

Inactivation of the tumor suppressor p53 is the predominant pathogenetic event in head and neck squamous cell carcinoma (HNSCC). The p53 pathway in HNSCC can be compro-mised through multiple mechanisms including gene mutations, hyperactivation of endogenous negative p53 regulators and by the human papillomavirus E6 protein. Inactivation of p53 is associated with poor clinical response and outcome;therefore, restoration of the p53 signaling cascade may be an effective approach to ablate HNSCC cells. Viral approaches to restore p53 activity in HNSCC have been well-studied and shown modest activity in clinical trials. Recent work has focused on high-throughput screens and rational designs to identify and develop small molecules to rescue p53 function. Several p53-targeting small molecules have demonstrated very promising activity in pre-clinical studies but have yet progressed to the clinical setting. Further development of p53 therapies, in particular chemical approaches, should be priori-tized and evaluated in the HNSCC setting. Copyright a 2016 Chinese Medical Association. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

USH2A mutation and specific driver mutation subtypes are associated with clinical efficacy of immune checkpoint inhibitors in lung cancer

This study aimed to identify subtypes of genomic variants associated with the efficacy of immune checkpoint inhibitors(ICIs)by conducting systematic literature search in electronic databases up to May 31,2021.The main outcomes including overall survival(OS),progression-free survival(PFS),objective response rate(ORR),and durable clinical benefit(DCB)were correlated with tumor genomic features.A total of 1546 lung cancer patients with available genomic variation data were included from 14 studies.The Kirsten rat sarcoma viral oncogene homolog G12C(KRAS^(G12C))mutation combined with tumor protein P53(TP53)mutation revealed the promising efficacy of ICI therapy in these patients.Furthermore,patients with epidermal growth factor receptor(EGFR)classical activating mutations(including EGFRL858Rand EGFRΔ19)exhibited worse outcomes to ICIs in OS(adjusted hazard ratio(HR),1.40;95%confidence interval(CI),1.01-1.95;P=0.0411)and PFS(adjusted HR,1.98;95%CI,1.49-2.63;P<0.0001),while classical activating mutations with EGFR^(T790)Mshowed no difference compared to classical activating mutations without EGFR^(T790)Min OS(adjusted HR,0.96;95%CI,0.48-1.94;P=0.9157)or PFS(adjusted HR,0.72;95%CI,0.39-1.35;P=0.3050).Of note,for patients harboring the Usher syndrome type-2A(USH2A)missense mutation,correspondingly better outcomes were observed in OS(adjusted HR,0.52;95%CI,0.32-0.82;P=0.0077),PFS(adjusted HR,0.51;95%CI,0.38-0.69;P<0.0001),DCB(adjusted odds ratio(OR),4.74;95%CI,2.75-8.17;P<0.0001),and ORR(adjusted OR,3.45;95%CI,1.88-6.33;P<0.0001).Our findings indicated that,USH2A missense mutations and the KRAS^(G12C)mutation combined with TP53 mutation were associated with better efficacy and survival outcomes,but EGFR classical mutations irrespective of combination with EGFR^(T790)Mshowed the opposite role in the ICI therapy among lung cancer patients.Our findings might guide the selection of precise targets for effective immunotherapy in the clinic.