Tumor infiltrating lymphocytes in gastric cancer:Unraveling complex interactions for precision medicine

This editorial will focus on tumor immunity and the factors that alter the tumor immune micro-environment.The role of tumor infiltrating lymphocytes(TILs)will also be discussed in detail,including the types,mechanism of action,and role.Gastric cancer(GC)often presents in the advanced stage and has various factors predicting the outcomes.The interplay of these factors and their correlation with the TILs is discussed.A literature review revealed high intratumoral TILs associated with higher grade,HER2-,and Helicobacter pylori negativity.Moreover,stromal(ST)TILs correlated with lower grade and lesser recurrence risk in GC.High TILs in ST and invasive border also correlated with mismatch repair deficiency status.Further characterization of the CD3+,CD8+,and other cells is also warranted.In the future,this complex correlation of cancer cells with the immune system can be explored for therapeutic avenues.

PREPARATION AND CYTOLYTIC TUMOR ACTIVITY OF OSTEOSARCOMA TUMOR INFILTRATING LYMPHOCYTES IN VITRO

In this study, the isolation, purification and differentiation of tumor-lnflltratlng lymphocytes (TIL) from 6 fresh osteosarcoma specimens were achieved by discontinuous density gradient centrifugation. One specimen of the osteosarcoma TIL were enlarged in IL-2 for long time in vitro, reaching 28 days and their cytolytic activity against different tumor cell lines was Investigated. The experimental results indicated that the preparation of osteosarcoma TIL adopted by the mechanical means was simple, having higher purifity, keeping higher effects on killing NK- sensitive tumor cell lines and NK-insensitive tumor cell lines as well as rapid proliferation in vitro cultured in IL-2.

The Tumor Infiltrating Lymphocytes (TILs): Did We Find the Missed Piece of the Huge Puzzle?

Tumor infiltrating lymphocytes (TILs) are used in evaluating the prognosis and determining treatment of different types of cancer with variable degrees of success. The usage of checkpoint inhibitor immunotherapy as a treatment variety for cancer and Adoptive cell therapy is associated with many complications, severe side effects and high expenses. Recently, in a limited number of metastatic GIT and breast cancers, the identification of T-cell specific against so-called tumor neo-antigens and Adoptive transfer of those lymphocytes resulted in some improvement. In 2020, Detection of a T cell receptor (TCR) in a T cell clone that recognized and killed most human cancer cell lines in vitro via the monomorphic MHC class I-related protein MR1, offers an opportunity for pan-cancer therapy Twenty three years earlier, Moist Heat was used successfully to activate a whole different and new immune response that was able to detect genetic mutation in the affected cancer cells and cured many cases of squamous and basal cell carcinomas. In this commentary review, we aimed to revise the literature for updates of TILs usage in cancer prognosis and treatment.

Association of tumor budding with clinicopathological features and prognostic value in stage III-IV colorectal cancer

BACKGROUND Tumor budding(TB)has emerged as a promising independent prognostic biomarker in colorectal cancer(CRC).The prognostic role of TB has been extensively studied and currently affects clinical decision making in patients with stage I and II CRC.However,existing prognostic studies on TB in stage III CRC have been confined to small retrospective cohort studies.Consequently,this study investigated the correlation among TB categories,clinicopathological features,and prognosis in stage III-IV CRC to further enhance the precision and individualization of treatment through refined prognostic risk stratification.AIM To analyze the relationship between TB categories and clinicopathological characteristics and assess their prognostic value in stage III-IV CRC to further refine the prognostic risk stratification of stage III-IV CRC.METHODS The clinical data of 547 CRC patients were collected for this retrospective study.Infiltration at the front edge of the tumor buds was counted according to the 2016 International Tumor Budding Consensus Conference guidelines.RESULTS Multivariate Cox proportional hazards regression analysis demonstrated that chemotherapy(P=0.004),clinical stage IV(P<0.001),≥4 regional lymph node metastases(P=0.004),left-sided colonic cancer(P=0.040),and Bd 2-3(P=0.002)were independent prognostic factors in patients with stage III-IV CRC.Moreover,the density of tumor infiltrating lymphocytes was higher in Bd 1 than in Bd 2-3,both in the tumor stroma and its invasive margin.CONCLUSION TB has an independent predictive prognostic value in patients with stage III-IV CRC.It is recommended to complete the TB report of stage III-IV CRC cases in the standardized pathological report to further refine risk stratification.

Immune signature of small bowel adenocarcinoma and the role of tumor microenvironment

In this editorial we comment on the article published“Clinical significance of programmed cell death-ligand expression in small bowel adenocarcinoma is determined by the tumor microenvironment”.Small bowel adenocarcinoma(SBA)is a rare gastrointestinal neoplasm and despite the small intestine's significant surface area,SBA accounts for less than 3%of such tumors.Early detection is challenging and the reason arises from its asymptomatic nature,often leading to late-stage discovery and poor prognosis.Treatment involves platinum-based chemotherapy with a 5-fluorouracil combination,but the lack of effective chemotherapy contributes to a generally poor prognosis.SBAs are linked to genetic disorders and risk factors,including chronic inflammatory conditions.The unique characteristics of the small bowel,such as rapid cell renewal and an active immune system,contributes to the rarity of these tumors as well as the high intratumoral infiltration of immune cells is associated with a favorable prognosis.Programmed cell death-ligand 1(PD-L1)expression varies across different cancers,with potential discrepancies in its prognostic value.Microsatellite instability(MSI)in SBA is associated with a high tumor mutational burden,affecting the prognosis and response to immunotherapy.The presence of PD-L1 and programmed cell death 1,along with tumor-infiltrating lymphocytes,plays a crucial role in the complex microenvironment of SBA and contributes to a more favorable prognosis,especially in the context of high MSI tumors.Stromal tumor-infiltrating lymphocytes are identified as independent prognostic indicators and the association between MSI status and a favorable prognosis,emphasizes the importance of evaluating the immune status of tumors for treatment decisions.

TREATMENT OF 23 PATIENTS WITH ADVANCED GASTRIC CANCER BY INTRAVENOUSLY TRANSFER OF AUTOLOGOUS TUMOR-INFILTRATING LYMPHOCYTES COMBINED WITH rIL-2

Tumor-infiltrating lymphocytes (TIL)isolated from metastatic lymph nodes in patients with nonoperable advanced gastric cancer were induced to become LAK-like cytotoxic activrty of TIL after in vitro culture with rlL-2.Twenty-three patients with advanced gastric cancer were treated by intravenously transfer of autologous TIL combined with rlL-2. The tumor forus disappeared (complete remission, CR) in 3 patients (13. 0%) and significantly decreased (partial remission, PR) in 5 patients (21. 7%). Fifteen patients did not respond to the treatment. The amount of soluable IL-2 receptor in serum was significantly decreased after treatment, the cytotoxicity of NK cells and OT test were significantly increased. No significant difference in CD4/CD8 was found between before and after treatment. No serious side effect was obseved in the treatment.

ISOLATION AND CULTURE OF TUMOR-INFILTRATING LYMPHOCYTES FROM MOUSE HEPATOMA

By uaing enzyme digestion and Flcoll- Hypaque or Percoll discontinuous density methods, we have successfully obtained tumor-infiltrating lymphocytes (TIL) from mouse hepatoma. When analyzing the purity of TIL after separation. It was found that Percoll was more effective than Flcoll (P<0. 01). TIL could be activated In the presence of recombinant lL-2 (rIL-2) and begin to expand after culturing for 5-7 days, the tumor cells tend to decrease and disappeared after 14 days or so. TIL increased 105-fold over 40 days. Conditioned medium containing supernatant of PHA and rIL- 2 stimulated syngeneic spleen cell culture could promote the expansion of TIL.

Morphological observation of tumor infiltrating immunocytes in human rectal cancer

AIM： To investigate the morphological characterization of tumor infiltrating dendritic cells （TIDCs） and tumor infiltrating lymphocytes （TILs） in human rectal cancer. METHODS： Light and electron microscopy as well as immunohistochemistry were used to observe the distributive and morphological changes of TIDCs and TILs. RESULTS： TIDCs were mainly located in tumor-surrounding tissue. The number of TIDCs in the earlier stage was higher than that in the later stage （P〈 0.01）. TILs were mainly seen in adjacent tissue of cancers and tumor-surrounding tissue. There were more TILs in the earlier stage than that in the later stage （P〈0.01）. Under electron microscope, TIDCs were irregular in shape and exhibited many dendritic protrusions. It isn＇t obvious that cancer cells perforated the basement membrane and TILs were arranged along the basement membrane in the earlier stage. In the later stage, it is explicit that cancer cells perforated the basement membrane and surrounded by TILs. There were contacts among TIDCs, TILs and tumor cell. One IIDCs contacted one or several TILs which clustered around TIDCs. Glycogen granules were seen between TIDCs and Tits. CONCLUSION： The number of TIDCs and TILs is related with tumor progression There exist close relationships among TIDCs, TILs and tumor cell.

Effect of Tumor Infiltrating Lymphocyte on Local Control of Rectal Cancer after Preoperative Radiotherapy

Objective： To study the effect of tumor infiltrating lymphocytes at cancer nest on local control of rectal cancer after preoperative radiotherapy. Methods： From Jan. 1999 to Oct. 2007, a total of 107 patients with rectal cancer were reviewed. They were treated by preoperative radiotherapy, 30 Gy/10 fractions/12 days. Two weeks later, the patient underwent a surgical operation. Their pathological samples were kept in our hospital before and after radiotherapy. Lymphocyte infiltration （LI） degree, pathologic degradation and fibrosis degree after radiotherapy in paraffin section were evaluated under microscope. Results： After followed-up of 21 months （2-86 months）, a total of 107 patients were reviewed. Univariate analysis showed that lymphocyte infiltration （LI）, fibrosis and pathologic changes after radiotherapy were significant factors on local control. Logistic regression analysis showed that LI after radiotherapy was a significant effect factor on local control. Conclusion： LI, fibrosis and pathologic degradation after radiotherapy are significant for local control of rectal cancer after preoperative radiotherapy. LI after radiotherapy was a significantly prognostic index for local control of rectal cancer after preoperative radiotherapy.

Invasive front of colorectal cancer:Dynamic interface of pro-/anti-tumor factors

Tumor-host interaction at the invasive front of colorectal cancer represents a critical interface encompassing a dynamic process of de-differentiation of colorectal carci-noma cells known as epithelial mesenchymal transition (EMT). EMT can be identified histologically by the presence of "tumor budding" ,a feature which can be highly specific for tumors showing an inf iltrating tumor growth pattern. Importantly,tumor budding and tumor border configuration have generated considerable interest as additional prognostic factors and are also recognized as such by the International Union Against Cancer. Evidence seems to suggest that the presence of tumor budding or an infiltrating growth pattern is inversely correlated with the presence of immune and inflammatory responses at the invasive tumor front. In fact,several tumor-associated antigens such as CD3,CD4,CD8,CD20,Granzyme B,FOXP3 and other immunological or inflammatory cell types have been identified as poten-tially prognostic in patients with this disease. Evidence seems to suggest that the balance between protumor (including budding and inf iltrating growth pattern) and anti-tumor (immune response or certain inflammatory cell types) factors at the invasive front of colorectal cancer may be decisive in determining tumor progression and the clinical outcome of patients with colorectal cancer. On one hand,the inf iltrating tumor border configuration and tumor budding promote progression and dissemination of tumor cells by penetrating the vascular and lymphatic vessels. On the other,the host attempts to fend off this attack by mounting an immune response to protect vascular and lymphatic channels from invasion by tumor buds. Whereas standard pathology reporting of breast and prostate cancer involves additional prognostic features,such as the BRE and Gleason scores,the ratio of pro-and anti-tumor factors could be a promising approach for the future development of a prognostic score for patients with colorectal cancer which could complement tumor node metastasis staging to improve the clinical management of patients with this disease.

Histological differentiation impacts the tumor immune microenvironment in gastric carcinoma:Relation to the immune cycle

BACKGROUND Various histological types of gastric carcinomas(GCs)differ in terms of their pathogenesis and their preexisting background,both of which could impact the tumor immune microenvironment(TIME).However,the current understanding of the immune contexture of GC is far from complete.AIM To clarify the tumor-host immune interplay through histopathological features and the tumor immune cycle concept.METHODS In total,50 GC cases were examined(15 cases of diffuse GC,31 patients with intestinal-type GC and 4 cases of mucinous GC).The immunophenotype of GC was assessed and classified as immune desert(ID),immune excluded(IE)or inflamed(Inf)according to CD8+cell count and spatial pattern.In addition,CD68+and CD163+macrophages and programmed death-ligand 1(PD-L1)expression were estimated.RESULTS We found that GCs with different histological differentiation demonstrated distinct immune contexture.Most intestinal-type GCs had inflamed TIMEs rich in both CD8+cells and macrophages.In contrast,more aggressive diffuse-type GC more often possessed ID characteristics with few CD8+lymphocytes but abundant CD68+macrophages,while mucinous GC had an IE-TIME with a prevalence of CD68+macrophages and CD8+lymphocytes in the peritumor stroma.PD-L1 expression prevailed mostly in intestinal-type Inf-GC,with numerous CD163+cells observed.Therefore,GCs of different histological patterns have specific mechanisms of immune escape.While intestinal-type GC was more often related to PD-L1 expression,diffuse and mucinous GCs possessing more aggressive behavior demonstrated low immunogenicity and a lack of tumor antigen recognition or immune cell recruitment into the tumor clusters.CONCLUSION These data help to clarify the links between tumor histogenesis and immunogenicity for a better understanding of GC biology and more tailored patient management.

Tumor-infiltrating lymphocytes in the immunotherapy era

The clinical success of cancer immune checkpoint blockade(ICB)has refocused attention on tumor-infiltrating lymphocytes(TILs)across cancer types.The outcome of immune checkpoint inhibitor therapy in cancer patients has been linked to the quality and magnitude of T cell,NK cell,and more recently,B cell responses within the tumor microenvironment.State-of-the-art single-cell analysis of TIL gene expression profiles and clonality has revealed a remarkable degree of cellular heterogeneity and distinct patterns of immune activation and exhaustion.Many of these states are conserved across tumor types,in line with the broad responses observed clinically.Despite this homology,not all cancer types with similar TIL landscapes respond similarly to immunotherapy,highlighting the complexity of the underlying tumor-immune interactions.This observation is further confounded by the strong prognostic benefit of TILs observed for tumor types that have so far respond poorly to immunotherapy.Thus,while a holistic view of lymphocyte infiltration and dysfunction on a single-cell level is emerging,the search for response and prognostic biomarkers is just beginning.Within this review,we discuss recent advances in the understanding of TIL biology,their prognostic benefit,and their predictive value for therapy.

Heparanase expression,degradation of basement membrane and low degree of infi ltration by immunocytes correlate with invasion and progression of human gastric cancer

AIM： To disclose the mechanisms that accelerate or limit tumor invasion and metastasis in gastric cancer patients. METHODS： The heparanase expression, continuity of basement, degree of infiltration by dendritic cells and lymphocytes in gastric cancer tissues from 33 the early and late stage patients were examined by immunohistochemistry, in situ hybridization and transmission electron microscopy. RESULTS： Heparanase mRNA expression in the late stage patients with gastric cancer was stronger than that in the early stage gastric cancer patients. In the early stage gastric cancer tissues, basement membrane （BM） appeared intact, whereas in the late stage, discontinuous BM was often present. The density of Sl00 protein positive tumor infiltrating dendritic cells （TIDC） in the early stage gastric cancer tissues was higher than that in the late stage. The infiltrating degree of tumor infiltrating lymphocytes （TIL） in the early stage patients whose tumor tissues contained a high density of TIDC was significantly higher than that in the late stage gastric cancer tissues patients with a low density of TIDC. There were few cancer cells penetrated through the continuous BM of cancer nests in the early stage gastric cancers, but many cancer cells were found outside of the defective BM of cancer nests in the late stage. CONCLUSION： Our results suggest that strongheparanase expression is related with the degradation of BM which allows or accelerates tumor invasion and metastasis. However, high density of TIDC and degree of infiltration by TIL are associated with tumor progression in human gastric cancers.

Immuno-oncology in triple-negative breast cancer

The immune system plays an important role in breast cancer.Triple-negative breast cancer(TNBC)has a higher mutational load compared to other subtypes.In addition,higher levels of tumor-associated antigens suggests that immunotherapies are a promising treatment option especially for TNBC.Our review discusses both the complexity of the immune system and the cancer immune-cell cycle.In fact,a higher level of tumor-infiltrating lymphocytes is associated with an improved prognosis as well as a better response to chemotherapy in TNBC.Important target structures within the cancer immune-cell cycle are the so-called“immune checkpoints”.Immune checkpoint inhibitors(ICPi)block the interaction of certain cell surface proteins that serve as“brakes”of immune reactions.Recent studies have shown ICPi improved survival in early as well as advanced TNBC.However,this has the price of increasing,mainly,immune-mediated toxicity.ICPi strengthen tumor-specific T cell-mediated immunity by“releasing the brake”of the immune system.In combination with chemotherapy,ICPi are already approved for TNBC.As a further step,individualized vaccination strategies against tumor-associated neoantigens represent another promising approach.A liposome-formulated intravenous RNA vaccine encoding different tumor-associated antigens is currently being studied in TNBC and leads to neoantigen-specific immune responses.These novel strategies will improve the prognosis of patients with triple-negative breast cancer.

Predictive molecular markers in the era of immunotherapy

Recent development in anticancer therapeutics has been centered on immune checkpoint inhibitors(ICIs).Despite early success of ICIs in several cancer types,majority of cancer patients do not respond to ICI therapy.Therefore,predictive biomarkers are urgently needed to select patients who would likely benefit from ICI therapy.Currently immunohistochemical(IHC)assay for programmed cell death ligand 1(PD-L1)and microsatellite instability(MSI)testing are the only Food and Drug Administration-approved predictive biomarkers for ICI therapies.Tumor mutation burden(TMB)and tumor infiltrating lymphocytes(TILs)are emerging markers,which may prove to be useful predictive markers for ICIs.The guidelines for MSI testing have been well established.However,rigorous quality controls and systemic standardization for PD-L1 IHC testing and analysis of TMB and TILs,such as sample selection,tissue fixation,assay/platform selection,scoring methods,and clinically meaningful cutoff values etc.are needed to improve their clinical utility as predictive biomarkers for ICI therapy.Studies have suggested that the results of PD-L1 expression in tumor cells from various PD-L1 IHC assays are concordant and may be interchangeable.However,the variations and poor interobserver concordance of PDL1 expression in immune cells is a major issue to be addressed for the interchangeability of different PD-L1 IHC assays,especially for carcinomas of the gastrointestinal tract.Development of new predictive biomarkers and better understanding the difference in tumor immune microenvironments between ICI-sensitive and ICI-resistant tumors will help to develop more effective strategies for immunotherapy.