Frequency of immunohistochemical loss of mismatch repair protein in double primary cancers of the colorectum and stomach in Japan

Mutual association between family history of gastric and colorectal cancer and risk of gastric and colorectal cancer

BACKGROUND AND AIM

We evaluated the associations between gastric cancer (GC) family history (FH) and colorectal cancer (CRC) risk and between CRC FH and GC/gastric adenoma risk.

METHODS

We used data of participants who underwent national cancer screening between 2013 and 2014. Participants with GC or CRC FH in first-degree relatives (n = 1 172 750) and those without cancer FH (n = 3 518 250) were matched 1:3 by age and gender.

RESULTS

Of the 1 172 750 participants with a FH, 871 104, 264 040, and 37 606 had FHs of only GC, only CRC, and both GC and CRC, respectively. The median follow-up time was 4.8 years. GC and CRC FHs were associated with increased GC and CRC risks, respectively. GC FH was associated with CRC risk (adjusted hazard ratio 1.05; 95% confidence interval [CI] 1.01-1.10), whereas CRC FH was not associated with the risk of GC or gastric adenoma. However, gastric adenoma risk increased 1.62-fold (95% CI 1.40-1.87) in participants with FHs of both GC and CRC, demonstrating a significant difference with the 1.39-fold (95% CI 1.34-1.44) increase in participants with only GC FH. Furthermore, GC risk increased by 5.32 times (95% CI 1.74-16.24) in participants with FHs of both GC and CRC in both parents and siblings.

CONCLUSIONS

GC FH was significantly associated with a 5% increase in CRC risk. Although CRC FH did not increase GC risk, FH of both GC and CRC further increased the risk of gastric adenoma. FHs of GC and CRC may affect each other's neoplastic lesion risk.

Protein expression-based classification of gastric cancer by immunohistochemistry of tissue microarray

Recently, the Cancer Genome Atlas and Asian Cancer Research Group propose two new classifications system of gastric cancer by using multi-platforms of molecular analyses. However, these highly complicated and cost technologies have not yet been translated into full clinical utility. In addition, the clinicians are expected to gain more guidance of treatment for different molecular subtypes. In this study, we developed a panel of gastric cancer patients in population from Southern China using commercially accessible TMA and immunohistochemical technology. A cohort of 259 GC patients was classified into 4 subtypes on the basis of expression of mismatch repair proteins (PMS2, MLH1, MSH2, and MSH6), E-cadherin and p21 protein. We observed that the subtypes presented distinct prognosis. dMMR-like subtype was associated with the best prognosis, and E-cadherin-a subtype was associated with the worst prognosis. Patients with p21-High and p21-Ligh subtypes had intermediate overall survival. In multivariate analysis, the dMMR-like subtype remained an independent prediction power for overall survival in the model. We described a molecular classification of gastric cancers using clinically applicable assay. The biological relevance of the four subtypes was illustrated by significant differences in prognosis. Our molecular classification provided an effective and inexpensive screening tool for improving prognostic models. Nevertheless, our study should be considered preliminary and carries a limited predictive value as a single-center retrospective study.

Clinicopathologic and Molecular Characteristics of Synchronous Colorectal Carcinoma With Mismatch Repair Deficiency

Synchronous colorectal carcinoma (CRC) is a unique disease associated with a high prevalence (∼35%) of microsatellite instability and occasionally with Lynch syndrome. The clinicopathologic and molecular features of synchronous CRC are poorly understood, particularly in Japanese patients. We examined 118 Japanese patients (236 tumors) with synchronous CRC and 117 Japanese patients (117 tumors) with solitary CRC with immunohistochemical staining for TP53 and mismatch repair (MMR) protein (MLH1, MSH2, PMS2, and MSH6) and mutation analyses of KRAS and BRAF genes. The results revealed no significant differences in clinicopathologic, histologic, and molecular findings between the synchronous and solitary CRC groups. Among the 118 synchronous CRC patients, 15 (12.7%) showed loss of MMR protein(s) expression in at least 1 tumor, whereas 103 (87.3%) showed intact expression of all 4 MMR proteins in both tumors. Of note, all patients with MMR deficiency had excellent prognoses. The 15 patients were further subdivided into 2 groups: the Concordant group, with concordant MMR loss (n=9, 7.6%) and the Discordant group, with discordant MMR loss (n=6, 5.1%). The Concordant patients showed concurrent MLH1/PMS2 loss (n=3), concurrent MSH2/MSH6 loss (n=4) and isolated MSH6 loss (n=2) in both tumors, whereas the Discordant patients showed concurrent MLH1/PMS2 loss (n=2), isolated PMS2 loss (n=2) and isolated MSH6 loss (n=2) in a single tumor. On the basis of the MMR expression pattern and BRAF mutation, the Concordant and Discordant groups were suspected to include Lynch syndrome, Lynch-like syndrome and sporadic MLH1 promoter hypermethylated CRC. In addition, KRAS mutation was present in only 1 tumor in a single patient in each group. In conclusion, the frequency of MMR protein deficiency in synchronous CRC in the Japanese population may be lower compared with the reported data from Western populations. MMR protein loss and KRAS and BRAF mutations in synchronous CRCs were heterogenous even in an individual patient.

Phenotypic and genotypic differences in colorectal carcinoma among Caucasians, Asians, and Hispanics lack statistical significance

Colorectal carcinoma (CRC) has been shown to have both genetic and environmental factors that can promote carcinoma development. Previous studies have found ethnic differences in the distribution of molecular phenotypes of CRC. Very little specific data exist regarding Hispanic CRC, and these data primarily focus on epidemiology or location of carcinoma. Our retrospective study analyzed 562 Caucasian, Asian, and Hispanic CRC patients at the UCI Medical Center from 2004 to 2012. The results showed that there were no statistically significant differences with respect to mean age, gender or site of carcinoma among the three ethnic groups. There were no statistically significant differences among the three ethnicities with respect to rates of MSI, mutated BRAF, and mutated KRAS. The Caucasian group had a non-significant higher rate of MSI (15%) and BRAF mutation (12%) than the Asian and Hispanic groups. Hispanics had a non-significant higher rate of KRAS mutation (59%) than Caucasians (38%) and Asians (37%). The results of this study demonstrated a higher rate of MSI and BRAF mutation in the Caucasian group and a higher rate of KRAS mutation in the Hispanic group, however differences were not statistically significant.

Association between Mismatch-repair Genetic variation and the Risk of Multiple Primary Cancers: A Meta-Analysis

Microsatellites instability (MSI) is a risk factor for multiple primary cancers (MPCs). However, a variety of studies focused on the risk in the hereditary non-polyposis colorectal cancer (HNPCC) not the sporadic colorectal cancer (CRC) patients. The aim of this meta-analysis was to comprehensive overview and quantitative summary the association between MSI and risk of MPCs. A comprehensive literature search in MEDLINE, EMBASE, Web of science, ScienceDirect, Weily and OVID was conducted. Up to May 2016, we identified 22 observational studies. We calculated the summary relative risk (RR) for the risk of MPCs in MSI patients compared with microsatellites stability (MSS) patients using fixed- or random-effects models. The RR of the association between mismatch-repair gene (MMR) genotype and MPCs was 2.59 (95% confidence interval [CI], 2.06 to 3.27); the RR was 2.14 (95% CI, 1.78 to 2.57) for sporadic CRC and 5.59 (95% CI, 2.69 to 11.59) for HNPCC for the MSI versus MSS category. The subgroup analyses showed different mutant gene, mutant locus, and mutant level of MMR with different influence on the patients susceptible to MPCs. In addition, MSI genotype increase the risk of MPC was not associated with an apparently specific in regard to site, timing, age and detection method. In conclusion, this meta-analysis indicates that MSI is associated with an increased risk of MPCs both in the HNPCC and sporadic CRC patients. Our findings will form the backbone of the treatment for MSI genotype may be an important valuable strategy for MPCs prevention.

Expression of Mismatch Repair Proteins in Early and Advanced Gastric Cancer in Poland

BACKGROUND Mutations in DNA of mismatch repair (MMR) genes result in failure to repair errors that occur during DNA replication in microsatellites, resulting in accumulation of frameshift mutations in these genes and leading to DNA mismatch replication errors and microsatellite instability. Gastric cancers (GCs) with high MSI (MSI-H) are a well-defined subset of carcinomas showing distinctive clinicopathological features. In this study we investigated the rate of MSI and the correlation between MSI status and clinicopathological features of GC. MATERIAL AND METHODS The study included 107 patients with GCs: 61 with advanced gastric cancers (AGC) and 46 with early gastric cancer (EGC). MSI deficiency in GCs was assessed by the immunohistochemical analysis of expression of MMR proteins - MLH1, MSH2, MSH6, and PMS2 - using formalin-fixed and paraffin-embedded tissue. RESULTS A total of 6 (5.6%) MSI-H were observed. The loss of MMR proteins expression was associated with the intestinal type of GC in Lauren classification, and tubular and papillary architecture in WHO classification. There was no statistically significant association between negative MMR expression and other selected clinical parameters: age, sex, tumor location, depth of invasion (EGC and AGC), lymph nodes status, presence of the ulceration, and lymphocytic infiltrate. CONCLUSIONS In the present era of personalized medicine, the histological type of GC and MMR proteins status in cancer cells are very important for the proper surveillance of patients with familial GC and sporadic GCs, as well as for selecting the proper follow-up and treatment. Larger collaborative studies are needed to verify the features of MSI-H GCs in Poland.

The analysis of microsatellite instability in extracolonic gastrointestinal malignancy

Microsatellite instability (MSI) is a genetic feature of sporadic and familial cancers of multiple sites and is related to defective mismatch repair (MMR) protein function. Lynch syndrome (LS) is a familial form of MMR deficiency that may present with a spectrum of MSI positive cancers including gastrointestinal (GI) malignancies. The incidence of high level MSI (MSI-H) in colorectal carcinoma is well defined in both familial and sporadic cases and these tumours portend a better overall prognosis in colorectal carcinoma (CRC). There are certain morphological features that suggest MSI-H CRC and international guidelines have been established for the evaluation of MSI in CRC. The prevalence and morphological features of extracolonic GI MSI-H tumours are less well documented. Furthermore, it is unclear whether the guidelines for the assessment of MSI in CRC are appropriate for application to extracolonic GI malignancies. This review aims to summarise the recent literature on MSI in extracolonic LS-related GI tract malignancies with special attention to the assessment of the MMR system by evaluation of specific microsatellite markers and/or immunohistochemical evaluation of MMR protein expression. The reported prevalence of sporadic and LS-related MSI-H tumours along with their associated unique morphological patterns and related prognostic or therapeutic implications will be discussed.

Clinical characteristics of colorectal cancer patients with a second primary cancer

PURPOSE

The incidence of colorectal cancer is increasing due to a westernized dietary lifestyle, and improvements in treatment and diagnostic tools have resulted in more patients being confirmed of having multiple primary cancers. However, studies regarding multiple primary cancers are insufficient. In this study, the clinical aspects of patients with primary multiple cancers, including colorectal cancers, were investigated, and the results were compared to those of patients with primary colorectal cancer only.

METHODS

Seven hundred eighteen patients who received surgery for colorectal cancer between March 2003 and September 2012 in CHA Medical Center were enrolled. A retrograde cohort was done for comparison of the two groups: those with and those without multiple primary cancer. The analysis was done according to sex, age, tumor location, tumor size, metastatic regional lymph-node number, vascular/lymphatic microinvasion, staging, tumor markers, microsatellite instability, and C/T subgroup of polymorphism in methylenetetrahydrofolate reductase.

RESULTS

Of the 718 subjects, 33 (4.6%) had multiple primary cancers: 12 (36.4%) synchronous and 21 (63.6%) metachronous. The malignancy most frequently accompanying colorectal cancer was gastric cancer, followed by thyroid, prostate, and esophageal malignancies in that order. In the comparison between groups, mean age, tumor location, and microsatellite instability showed statistically significant differences; others parameters did not.

CONCLUSION

The incidence of multiple primary cancers, including colorectal cancer, is increasing. Therefore, defining the characteristics of patients with multiple primary cancers is crucial, and those characteristics need to be acknowledged in the follow-up of colorectal cancer patients.