Mismatch repair gene defects in sporadic colorectal cancer enhance immune surveillance

High prevalence of unusual KRAS, NRAS and BRAF mutations in POLE hypermutated colorectal cancers

Exonucleasic domain POLE (edPOLE) mutations, which are responsible for a hypermutated tumor phenotype, occur in 1–2% of colorectal cancer (CRC) cases. These alterations represent an emerging biomarker for response to immune checkpoint blockade. This study aimed to assess the molecular characteristics of edPOLE‐mutated tumors to facilitate patient screening. Based on opensource data analysis, we compared the prevalence of edPOLE mutations in a control group of unselected CRC patients (n = 222) vs a group enriched for unusual BRAF/RAS mutations (n = 198). Tumor mutational burden (TMB) and immune infiltrate of tumors harboring edPOLE mutations were then analyzed. In total, 420 CRC patients were analyzed: 11 edPOLE‐mutated tumors were identified, most frequently in microsatellite (MMR)‐proficient young (< 70 years) male patients, with left‐sided tumors harboring noncodon 12 KRAS mutation. The prevalence of edPOLE‐mutated tumors in the control vs the experimental screening group was, respectively, 0.45% (n = 1) vs 5.0% (n = 10). Among the 11 edPOLE‐mutated cases, two had a low TMB, three were hypermutated, and six were ultramutated. EdPOLE‐mutated cases had a high CD8⁺ tumor‐infiltrating lymphocyte (TIL) infiltration. These clinicopathological and molecular criteria may help to identify edPOLE mutations associated with a high TMB in CRC, and improve the selection of patients who could benefit from immunotherapy.

MSH2-deficient prostate tumours have a distinct immune response and clinical outcome compared to MSH2-deficient colorectal or endometrial cancer

BACKGROUND

Recent publications have shown patients with defects in the DNA mismatch repair (MMR) pathway driven by either MSH2 or MSH6 loss experience a significant increase in the incidence of prostate cancer. Moreover, this increased incidence of prostate cancer is accompanied by rapid disease progression and poor clinical outcomes.

METHODS AND RESULTS

We show that androgen-receptor activation, a key driver of prostate carcinogenesis, can disrupt the MSH2 gene in prostate cancer. We screened tumours from two cohorts (recurrent/non-recurrent) of prostate cancer patients to confirm the loss of MSH2 protein expression and identified decreased MSH2 expression in recurrent cases. Stratifying the independent TCGA prostate cancer cohort for MSH2/6 expression revealed that patients with lower levels of MSH2/6 had significant worse outcomes, in contrast, endometrial and colorectal cancer patients with lower MSH2/6 levels. MMRd endometrial and colorectal tumours showed the expected increase in mutational burden, microsatellite instability and enhanced immune cell mobilisation but this was not evident in prostate tumours.

CONCLUSIONS

We have shown that loss or reduced levels of MSH2/MSH6 protein in prostate cancer is associated with poor outcome. However, our data indicate that this is not associated with a statistically significant increase in mutational burden, microsatellite instability or immune cell mobilisation in a cohort of primary prostate cancers.

Targeting the DNA damage response in immuno-oncology: developments and opportunities

Immunotherapy has revolutionized cancer treatment and substantially improved patient outcome with regard to multiple tumour types. However, most patients still do not benefit from such therapies, notably because of the absence of pre-existing T cell infiltration. DNA damage response (DDR) deficiency has recently emerged as an important determinant of tumour immunogenicity. A growing body of evidence now supports the concept that DDR-targeted therapies can increase the antitumour immune response by (1) promoting antigenicity through increased mutability and genomic instability, (2) enhancing adjuvanticity through the activation of cytosolic immunity and immunogenic cell death and (3) favouring reactogenicity through the modulation of factors that control the tumour-immune cell synapse. In this Review, we discuss the interplay between the DDR and anticancer immunity and highlight how this dynamic interaction contributes to shaping tumour immunogenicity. We also review the most innovative preclinical approaches that could be used to investigate such effects, including recently developed ex vivo systems. Finally, we highlight the therapeutic opportunities presented by the exploitation of the DDR-anticancer immunity interplay, with a focus on those in early-phase clinical development.

The role of immunogenic cell death in gastrointestinal cancer immunotherapy (Review)

Modern cancer immunotherapy techniques are aimed at enhancing the responses of the patients' immune systems to fight against the cancer. The main promising strategies include active vaccination of tumor antigens, passive vaccination with antibodies specific to cancer antigens, adoptive transfer of cancer-specific T cells and manipulation of the patient's immune response by inhibiting immune checkpoints. The application of immunogenic cell death (ICD) inducers has been proven to enhance the immunity of patients undergoing various types of immunotherapy. The dying, stressed or injured cells release or present molecules on the cell surface, which function as either adjuvants or danger signals for detection by the innate immune system. These molecules are now termed 'damage-associated molecular patterns'. The term 'ICD' indicates a type of cell death that triggers an immune response against dead-cell antigens, particularly those derived from cancer cells, and it was initially proposed with regards to the effects of anticancer chemotherapy with conventional cytotoxic drugs. The aim of the present study was to review and discuss the role and mechanisms of ICD as a promising combined immunotherapy for gastrointestinal tumors.

Microsatellite Instability as a Predictor of Outcomes in Colorectal Cancer in the Era of Immune-Checkpoint Inhibitors

The microsatellite instable phenotype resulting from errors in DNA mismatch repair proteins accounts for as far as 15 to 20% of non-hereditary colon cancers but is scarce in rectal cancer. It has been shown that the increased existence of tumor-specific neoantigens in hypermutated tumors is correlated with higher tumor-infiltrating lymphocytes (TILs) and overexpression of immune checkpoint receptors and ligands, mainly PD-1 and PD-L1. In particular, the data gained up to now gives evidence that neoantigen recognition constitutes a dominant component in the course of immunotherapies. This review's primary objective is to describe current approvals and summarize present knowledge about the outcomes of immuno-oncology treatment of microsatellite instable colorectal cancer (CRC). The secondary objective is to give a narrative report about testing methodologies, prognostics, and the predictive value of microsatellite instability. For this purpose, a literature review was performed, focusing on published clinical trial results, ongoing clinical trials and timelines, testing methods, and prognostic and predictive value of MSI. Following four recent FDA approvals of immunotherapy of MSI-high CRC, further work should be warranted by pathology societies towards standardization and rising concordance and reproducibility across the IHC/MSI testing landscape in order to facilitate professionals to offer better survival options for patients with CRC.

MLH1 Deficiency Down-Regulates TLR4 Expression in Sporadic Colorectal Cancer

Patients with mismatch repair (MMR)-deficient colorectal cancer (CRC) have a more favorable prognosis than patients with tumors with intact MMR. In order to obtain further insights on the reasons for this different outcome, we investigated the interplay between MMR genes and TLR4/MyD88 signaling. The cancer genome atlas (TCGA) databases were selected to predict the differential expression of TLR4 in colon cancer and its correlation with MMR genes. Moreover, the expression of MMR genes and TLR4 was evaluated by immunohistochemistry in 113 CRC samples and a cohort of 63 patients was used to assess TLR4 mRNA expression and MLH1 epigenetic silencing status. In vitro, the effect of MLH1 knockdown on TLR4 expression was quantified by Real Time PCR. TLR4 expression resulted dependent on MMR status and directly correlated to MLH1 expression. In vitro, MLH1 silencing decreased TLR4 expression. These observations may reflect the better prognosis and the chemoresistance of patients with CRC and MMR defects.

CD80 expression is upregulated by TP53 activation in human cancer epithelial cells

CD80 is recognized as one of the most potent costimulatory molecules by which immune cells limit cancer progression; however, the current understanding of the regulation of its expression on human tumor cells is limited. The TP53 tumor suppressor plays a critical role in cancer and its significant role in the control of immune responses is emerging. Here, we evaluated the role of TP53 as a regulator of CD80 expression in human cancer cells. A set of well-known TP53-reactivating compounds were used on TP53-wild-type, TP53-deficient, TP53-mutated and TP53-knockdown cancer cell lines to determine if TP53 can regulate CD80. CD80 expression was analyzed in samples from patients with TP53-active vs TP53-inactive Colon Adenocarcinomas (COAD) from TCGA panCancer Atlas. We report that the pharmacological activation of TP53 can stimulate the expression of CD80 in human tumor cells of epithelial origin. We also provide evidence that CD80 expression exhibits a strong correlation with TP53 activation in a subgroup of colon tumors with better overall survival. These results confirm the link between TP53 and immune surveillance in human cancer and provide the possibility that conventional TP53-activation approaches for tumoricidal effects may be repurposed for immunotherapy strategies.

The purification of pectin from commercial fruit flours results in a jaboticaba fraction that inhibits galectin-3 and colon cancer cell growth

Fruits are a prime source of nutrients, bioactive compounds, and dietary fibers. Some products available on the Brazilian market use fruit by-products and claim to have useful effects on human health due to their dietary fiber content. The study aimed to extract and purify the total (28-47 w/w yield) and soluble dietary fiber (4-7 w/w yield) from jaboticaba, papaya, and plum commercial flours sold in Brazil and to study the in vitro biological effects of the fractions. The purified water-soluble fractions consisted mainly of pectin-derived oligosaccharides (5-15 KDa molecular weight) with a negligible content of polyphenols, protein, ashes, and starch. Jaboticaba sample was 95% galacturonic acid while plum and papaya samples were 40% galacturonic acid and 40% galactose (mol%), approximately. The samples were tested for recombinant human galectin-3 inhibition and changes in the cell viability of human colorectal cancer cells. Only the jaboticaba sample inhibited galectin-3 and decreased HCT116 cell viability after 48 h of treatment (p ≤ 0.01) while the plum sample decreased the cell viability after 24 h treatment (p ≤ 0.05). The results obtained in this study demonstrate the relationship between the structure of the soluble fibers extracted from jaboticaba flour and the possible beneficial effects of their consumption.

Synchronous nodal metastatic risk in screening detected and endoscopically removed pT1 colorectal cancers

BACKGROUND

The population screening campaigns have resulted in increasing the prevalence of endoscopically resected colorectal cancers (CRCs) invading the submucosa (pT1). Synchronous nodal involvement occurs in less than 15 % of these tumors. Histologic criteria currently used for selecting patients needing resection are imprecise and most patients could have been simply followed-up. Tumor infiltrating lymphocytes (TILs) and mismatch repair (MMR) status impact on CRC prognosis. To identify patients requiring completion surgery, the value of histologic variables, TILs and MMR status as risk factors of nodal metastasis was investigated in screening detected and endoscopically removed pT1 CRCs.

METHODS

In 102 endoscopically resected pT1 CRCs, the cancer phenotype, CD3+ and CD8+ TILs, and MMR status were assessed. Univariate and multivariate analyses were used to evaluate the correlation with nodal metastasis.

RESULTS

Positive resection margin, evidence of vascular invasion and tumor budding, wide area of submucosal invasion, and high number of CD3+ TILs were associated with nodal metastasis in univariate analyses. Vascular invasion was statistically independent in multivariate analysis. Evidence of neoplastic cells in the vessels and/or at the excision border featured 5 out of 5 metastatic tumors and 13 out of 97 non-metastatic ones.

CONCLUSIONS

Completion surgery should be recommended only in pT1 CRC with vascular invasion or with tumor cells reaching the margin. In all other cases, the treatment choice should result from a multidisciplinary discussion on the patient-centered evaluation of the risk-benefit ratio.

Expression status of four mismatch repair proteins in patients with colorectal cancer: clinical significance in 1238 cases

To investigate the expression of mismatch repair proteins (MMR) in colorectal cancer (CRC) and to analyze the correlation between MMR and pathologic features of CRC, immunohistochemistry was used to detect the expression of four MMR proteins (MLHl, PMS2, MSH2 and MSH6). All expression was classified as MMR proficient (pMMR). Absence of one or more of these proteins was classified as MMR deficient (dMMR). Among the 1238 cases of CRC, the four protein expression deletion rates from high to low were: PMS2 5.09% (63/1,238), MLH1 3.47% (43/1,238), MSH6 2.83% (35/1,238), and MSH2 2.10% (26/1,238). The dMMR cases accounted for 8.08% of all CRC cases (100/1,238). The common deletion rates of two or more proteins from high to low were: MLH1/PMS2 41.00% (41/100), MSH2/MSH6 20.00% (20/100), MSH6/PMS 23.00% (3/100), MLH1/MSH2/MSH6/PMS2 1.00% (1/100). dMMR cases were more common than pMMR cases in the ascending colon, T4 stage, stage II group, and poorly-differentiated CRC (P<0.05). MLH1 and PMS2 protein expression deficiency were correlated with tumor site, T stage, and differentiation. The incidence in ileocecum, T4, and poorly differentiated CRC was higher (P<0.05), and these two were positively correlated (P<0.05). The deficiency of MSH2 and MSH6 proteins was correlated with age, tumor site, and TNM stage; it was higher in patients ≤65 years old, in the transverse colon-splenic flexure region, and in stage II CRC (P<0.05), and the two were positively correlated (P<0.05). A co-expression deficiency of MLH1/PMS2 and MSH2/MSH6 was more common. The incidence of dMMR was more common in ascending colon, T4 stage, stage II, and poorly differentiated CRC. This may provide more comparisons and reference data for the molecular mechanism, clinical treatment, and prognosis of CRC.

Epithelial CD80 promotes immune surveillance of colonic preneoplastic lesions and its expression is increased by oxidative stress through STAT3 in colon cancer cells

BACKGROUND

One of the most potent costimulatory molecules involved in the recognition and killing of tumor cells is CD80. However, its role and the molecular mechanisms regulating its expression in sporadic colorectal carcinogenesis remain elusive. Here, we provide evidence for CD80 overexpression in human colon epithelial cells derived from preneoplastic mucosa.

METHODS

Expression of CD80 on colonic epithelial cells isolated from normal human colonic mucosa, preneoplastic and neoplastic specimens was assessed by flow cytometry. WT and CD80KO mice received azoxymethane to induce colon preneoplastic lesions and sacrificed to perform histology, flow cytometry analysis and immunohistochemistry of colonic mucosa. Some WT mice were treated with a monoclonal anti-CD80 antibody following AOM administration. Primary colon epithelial cells and CT26 cell line were used to quantify the expression of CD80 in response to pro-oxidant stimuli. Specific pharmacological inhibitors and siRNA silencing were used to inhibit MAPK pathways and STAT3.

RESULTS

CD80 expression was significantly increased in colon epithelial cells of human preneoplastic lesions. In the AOM model, CD80 impairment by administration of neutralizing antibodies or use of CD80 knockout mice enhanced dysplasia development. In vitro, CD80 upregulation was induced by oxidative stress in colon cancer cells and primary colon epithelial cells. In addition, reactive oxygen species could induce CD80 expression via the JNK and p38 MAPK pathways, that activated STAT3 transcription factor in colon cancer epithelial cells.

CONCLUSION

This study provide evidence for a major role of CD80 in orchestrating immune surveillance of colon preneoplastic lesions and might help to develop novel approaches that exploit anti-tumor immunity to prevent and control colon cancer.

Prognostic Value of Mismatch Repair Genes for Patients With Colorectal Cancer: Meta-Analysis

DNA mismatch repair was proposed to play a pivotal role in the development and prognosis of colorectal cancer. However, the prognostic value of mismatch repair on colorectal cancer is still unknown. The PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched. The articles about mismatch repair (including hMLH1, hMSH2, hMSH3, hMSH6, hPMSH1, and hPMSH2) deficiency for the prognosis of patients with colorectal cancer were included in the study. The hazard ratio and its 95% confidence interval were used to measure the impact of mismatch repair deficiency on survival time. Twenty-one articles were included. The combined hazard ratio for mismatch repair deficiency on overall survival was 0.59 (95% confidence interval: 0.50-0.69) and that on disease-free survival was 0.57 (95% confidence interval: 0.43-0.75). In subgroup analysis, there were a significant association between overall survival and mismatch repair deficiency in Asian studies (hazard ratio: 0.67; 95% confidence interval: 0.50-0.91) and Western studies (hazard ratio: 0.56; 95% confidence interval: 0.46-0.67). For disease-free survival, the hazard ratios in Asian studies and Western studies were 0.55 (95% confidence interval: 0.38-0.81) and 0.62 (95% confidence interval: 0.50-0.78), respectively. Our meta-analysis indicated that mismatch repair could be used to evaluate the prognosis of patients with colorectal cancer.

Exploiting DNA repair defects in colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer‐related deaths worldwide. Therapies that take advantage of defects in DNA repair pathways have been explored in the context of breast, ovarian, and other tumor types, but not yet systematically in CRC. At present, only immune checkpoint blockade therapies have been FDA approved for use in mismatch repair‐deficient colorectal tumors. Here, we discuss how systematic identification of alterations in DNA repair genes could provide new therapeutic opportunities for CRCs. Analysis of The Cancer Genome Atlas Colon Adenocarcinoma (TCGA‐COAD) and Rectal Adenocarcinoma (TCGA‐READ) PanCancer Atlas datasets identified 141 (out of 528) cases with putative driver mutations in 29 genes associated with DNA damage response and repair, including the mismatch repair and homologous recombination pathways. Genetic defects in these pathways might confer repair‐deficient characteristics, such as genomic instability in the absence of homologous recombination, which can be exploited. For example, inhibitors of poly(ADP)‐ribose polymerase are effectively used to treat cancers that carry mutations in BRCA1 and/or BRCA2 and have shown promising results in CRC preclinical studies. HR deficiency can also occur in cells with no detectable BRCA1/BRCA2 mutations but exhibiting BRCA‐like phenotypes. DNA repair‐targeting therapies, such as ATR and CHK1 inhibitors (which are most effective against cancers carrying ATM mutations), can be used in combination with current genotoxic chemotherapies in CRCs to further improve therapy response. Finally, therapies that target alternative DNA repair mechanisms, such as thiopurines, also have the potential to confer increased sensitivity to current chemotherapy regimens, thus expanding the spectrum of therapy options and potentially improving clinical outcomes for CRC patients.

CD39+ regulatory T cells accumulate in colon adenocarcinomas and display markers of increased suppressive function

Increasing knowledge of the function and regulation of tumor-infiltrating lymphocytes has led to new insights in cancer immunotherapy. Regulatory T cells (Treg) accumulate in colon tumors, and we recently showed that CD39⁺ Treg from cancer patients inhibit transendothelial migration of conventional T cells. CD39 mediates the hydrolysis of ATP to immunosuppressive adenosine and adds to the immunosuppressive effects of Treg. Here, we further investigated the regulatory features of intratumoral CD39⁺ Treg in colon cancer. Using flow cytometry analyses of cells from 46 colon cancer patients, we confirm the accumulation of CD39⁺ Treg in the tumor tissue compared to unaffected colon tissue, and also show that tumor-infiltrating Treg express more CD39 and Foxp3 on a per cell basis. Furthermore, CD39⁺ Treg in tumors express markers indicating increased turnover and suppressive ability. In particular, tumor-infiltrating CD39⁺ Treg have high expression of surface molecules related to immunosuppression, such as ICOS, PD-L1 and CTLA-4. Functional suppression assays also indicate potent suppressive capacity of CD39⁺ Treg on proliferation and IFN-γ secretion by conventional T cells. In conclusion, our results identify tumor-infiltrating CD39⁺ Treg as a numerous and potentially important immunosuppressive subset, and suggest that immunotherapy aimed at reducing the activity of CD39⁺ Treg may be particularly useful in the setting of colon cancer.

Intratumoral immune-biomarkers and mismatch repair status in leiyomyosarcoma -potential predictive markers for adjuvant treatment: a pilot study

Leiomyosarcoma is the second most frequent soft-tissue sarcoma. Tumor lymphocytic infiltration (TIL) and programed cell death ligand-1 (PD-L1) have been associated with prognosis in different malignancies while DNA mismatch-repair deficiency (MMR-D) has been associated with response to check-point inhibitors. In this pilot study, we sought to examine TIL, PD-L1 and mismatch-repair (MMR) protein expression in 11 leiomyosarcoma and its association with outcome as potential biomarkers for adjuvant treatment. Eleven primary leiomyosarcoma archived-tissues were analyzed for expression of MMR proteins (MSH2, MLH1, MSH6 and PSM2), PD-L1 expression and PD-1, CD3 or CD8. MMR-D was detected in tumor tissue from 2/11 leiomyosarcoma patients. CD3 T-cells were present in all samples, whereas CD8 staining was positive in all but one. PDL-1 was positive in 4/11 and PD-L1 in 6/11. Interestingly, the three patients with the poorest outcome had strongly positive staining for PD-L1 and CD8 while in the two patients who are alive and recurrence-free, both PD-L1 and CD8 infiltration were lacking. We found an association between tumor infiltrating CD8 cytotoxic lymphocytes, strong PD-L1 staining and survival; suggesting a role as biomarkers for treatment decisions regarding peri-operative chemotherapy. We also identified MMR-D in two patients with leiomyosarcoma comprising 18% of our sample.

Effects of immune suppression for transplantation on inflammatory colorectal cancer progression

Background

Ulcerative colitis patients and transplant recipients are at risk for colorectal cancer. Here, we show that immunosuppressive regimens for kidney transplants are associated with the progression of ulcerative colitis-related carcinogenesis.

Methods

We describe the case of a patient diagnosed with colorectal cancer in ulcerative colitis while on immunosuppressive therapy for a kidney transplant. The immunological microenvironment of the cancer and its mutational status were analyzed, and a mouse colon cancer model was created to replicate the unique clinical conditions. AOM/DSS mice were randomized into seven experimental groups that received different immunosuppressants and an untreated control group to assess the frequencies of adenocarcinoma and high-grade dysplasia. Histopathology, immunohistochemistry, and flow cytometry were also performed on the harvested mouse colons.

Results

All mice treated with an immunosuppressive regimen developed at least an adenoma, and several of those receiving anti-CD3, anti-CD8, and mycophenolate mofetil also developed adenocarcinomas. In contrast, mice receiving rapamycin did not develop adenocarcinomas, and the extent of high-grade dysplasia in those mice was similar to that in control mice.

Conclusions

Patients with pre-neoplastic conditions, such as ulcerative colitis, who are undergoing a solid organ transplant might benefit from the use of mTOR inhibitors given their intrinsic anti-tumor properties.

Among transplant recipients, colorectal cancer is more aggressive. This report highlights the association between immunosuppression and the disruption of the immune surveillance mechanisms against colorectal cancer.

Independent prognostic role of PD-L1expression in patients with esophageal squamous cell carcinoma

Accumulating evidence has shown that PD-L1 expression is associated with clinicopathological features in various human malignancies. We searched for correlations between PD-L1 expression and clinicopathological data in esophageal squamous cell carcinoma (ESCC) patients. PD-L1 expression in primary tumors from 278 patients was evaluated using immunohistochemistry (IHC) in ESCC tissue microarray. Survival curves were constructed by using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazard regression models were performed to identify associations with outcome variables. Overall, tumoral PD-L1 expression (≥10%, 20% or 30% as cut-off value) was associated with favorable DFS and OS upon multivariate analysis. When the patients stratified into stage I-II (168, 60.4%) and stage III-IV (110, 39.6%), or with lymph node metastasis (133, 47.8%), the prognostic role was not consistent. In patients with stage I-II disease, tumoral PD-L1 expression (≥5%, 10%, 20% or 30%) was associated with better DFS and OS upon multivariate analysis. In patients without lymph node metastasis, tumoral PD-L1 expression (≥1%, 5%, 10%, 20%, or 30%) was associated with improved DFS and OS in univariate or multivariate analysis. However, PD-L1 expression was not correlated with prognosis in patients with stage III-IV disease or with lymph node metastasis. Our results for the first time showed the prognostic role of tumoral PD-L1 expression was variable in different stages and lymph node status of ESCC. Tumoral PD-L1 expression was independent favorable predictor in ESCC patients with Stage I-II disease or without lymph node metastasis, not in stage III-IV or lymph node metastasis.

Tumors with unmethylated MLH1 and the CpG island methylator phenotype are associated with a poor prognosis in stage II colorectal cancer patients

We previously developed a novel tumor subtype classification model for duodenal adenocarcinomas based on a combination of the CpG island methylator phenotype (CIMP) and MLH1 methylation status. Here, we tested the prognostic value of this model in stage II colorectal cancer (CRC) patients. Tumors were assigned to CIMP+/MLH1-unmethylated (MLH1-U), CIMP+/MLH1-methylated (MLH1-M), CIMP−/MLH1-U, or CIMP−/MLH1-M groups. Age, tumor location, lymphovascular invasion, and mucin production differed among the four patient subgroups, and CIMP+/MLH1-U tumors were more likely to have lymphovascular invasion and mucin production. Kaplan-Meier analyses revealed differences in both disease-free survival (DFS) and overall survival (OS) among the four groups. In a multivariate analysis, CIMP/MLH1 methylation status was predictive of both DFS and OS, and DFS and OS were shortest in CIMP+/MLH1-U stage II CRC patients. These results suggest that tumor subtype classification based on the combination of CIMP and MLH1 methylation status is informative in stage II CRC patients, and that CIMP+/MLH1-U tumors exhibit aggressive features and are associated with poor clinical outcomes.

Colorectal cancer in the young: a possible role for immune surveillance?

BACKGROUND

Younger patients with colorectal cancer (CRC) generally have better survival in spite of worse clinical and pathological features.

METHODS

Twenty-six patients under 50 years operated for primary CRC were enrolled and matched 1:2:2 according to stage, tumor site and gender with 52 patients from 50 to 70 years and 52 patients over 70 years old.

RESULTS

Patients under 50 years had a significantly longer overall, cancer specific and disease free survival (p = .001, p = .007 and p = .05, respectively). However, they had more frequently lymphovascular invasion (p = .006) and they more frequently developed metachronous CRC at follow-up (p = .03). Nevertheless, preoperative lymphocytes blood count/white blood count (LBC/WBC) ratio inversely correlated with age at operation (rho = -.21, p = .04) and it predicted CRC recurrence with an accuracy of 70%, p < .001 (threshold value LBC/WBC = 0.21%) and better overall, cancer specific and disease free survival (p < .0001 for all). At multivariate analysis, stage and LBC/WBC ratio resulted independent predictors of disease free survival (p = .0001 and p = .01, respectively).

CONCLUSIONS

Patients under 50 years had a significantly longer survival with a higher LBC/WBC ratio. These results could suggest a possible role of immunosurveillance in neoplastic control.

Prospect for immune checkpoint blockade: dynamic and comprehensive monitorings pave the way

Immune checkpoint blockade, which releases the brake of the immune system to enhance anticancer immune response, stands out in the cancer immunotherapy field due to their remarkable and long-lasting effect. However, the overall response rate for currently approved immune checkpoint inhibitors is only about 10-40%. We have summarized three major components, which are the presence of checkpoints, the immune-activation mechanism and the immune-inhibitory mechanism, containing six factors to describe the cancer-immune interaction dynamically and comprehensively, which shed light on promising biomarkers in immune checkpoint therapy.

Single nucleotide polymorphisms in MLH1 predict poor prognosis of hepatocellular carcinoma in a Chinese population

Hepatocellular carcinoma (HCC) is a malignant cancer causing deleterious health effect worldwide, especially in China. So far clinical cure rate and long-term survival rate of HCC remains low. Most HCC patients after cancer resection have recurrence or metastasis within 5 years. This study aims to explore the genetic association of mutL homolog 1 (MLH1) polymorphisms with HCC risk and prognosis. Four candidate MLH1 polymorphisms, rs1800734, rs10849, rs3774343 and rs1540354 were studied from a hospital-based case-control study including 1,036 cases (HCC patients) and 1,036 controls (non-HCC patients) in Guangxi, China. All these SNPs interacted with environmental risk factors, such as HBV infection, alcohol intake and smoking in the pathogenesis of HCC. However, only rs1800734 had significant difference between cases and controls. Compared to the AA genotype, patients with AG, GG and AG/GG genotype of rs1800734 had an increased risk of HCC [ORs (95% CI) = 1.217 (1.074∼1.536), 1.745 (1.301∼2.591) and 1.291 (1.126∼1.687)] and a decreased survival time [co-dominant, HR (95% CI) = 1.553 (1.257∼1.920); dominant, HR (95% CI) = 2.207 (1.572∼3.100)]. Furthermore, we found that tumor number, tumor staging, metastasis and rs1800734 were associated with the overall survival of HCC patients by multivariate COX regression analysis. No significant difference was found between the other three MLH1 polymorphisms with HCC risk and prognosis. Our study suggests MLH1 SNP, rs1800734 as a new predictor for poor prognosis of HCC patients.

Construction and analysis of tissue microarrays in the era of digital pathology: a pilot study targeting CDX1 and CDX2 in a colon cancer cohort of 612 patients

CDX1 and CDX2 are possibly predictive biomarkers in colorectal cancer. We combined digitally‐guided (next generation) TMA construction (ngTMA) and the utility of digital image analysis (DIA) to assess accuracy, tumour heterogeneity and the selective impact of different combined intensity‐percentage levels on prognosis.CDX1 and CDX2 immunohistochemistry was performed on ngTMAs covering normal tissue, tumour centre and invasive front. The percentages of all epithelial cells per staining intensity per core were analysed digitally. Beyond classical prognosis analysis following REMARK guidelines, we investigated pre‐analytical conditions, three different types of heterogeneity (mosaic‐like, targeted and haphazard) and influences on cohort segregation and patient selection. The ngTMA‐DIA approach produced robust biomarker data with infrequent core loss and excellent on‐target punching. The detailed assessment of tumour heterogeneity could – except for a certain diffuse mosaic‐like heterogeneity – exclude differences between the invasive front and tumour centre, as well as detect haphazard clonal heterogeneous elements. Moreover, lower CDX1 and CDX2 counts correlated with mucinous histology, higher TNM stage, higher tumour grade and worse survival (p < 0.01, all). Different protein expression intensity levels shared comparable prognostic power and a great overlap in patient selection. The combination of ngTMA with DIA enhances accuracy and controls for biomarker analysis. Beyond the confirmation of CDX1 and CDX2 as prognostically relevant markers in CRC, this study highlights the greater robustness of CDX2 in comparison to CDX1. For the assessment of CDX2 protein loss, cut‐points as percentage data of complete protein loss can be deduced as a recommendation.