Prognostic significance of microsatellite instability determined by immunohistochemical staining of MSH2 and MLH1 in sporadic T3N0M0 colon cancer

A collaborative review of the microsatellite instability/deficient mismatch repair phenotype in patients with upper tract urothelial carcinoma

OBJECTIVE

To perform a collaborative review of the literature exploring the microsatellite instability/deficient mismatch repair (MSI/dMMR) phenotype in patients with upper tract urothelial carcinoma (UTUC).

METHOD

A collaborative review of the literature available on Medline was conducted by the Cancer Committee of the French Association of Urology to report studies describing the genetic mechanisms, investigation, prevalence and impact of the MSI/dMMR phenotype in UTUC patients.

RESULTS

The predominant genetic mechanism leading to the MSI/dMMR phenotype in UTUC patients is related to the constitutional mutation of one allele of the MMR genes MLH1, MSH2, MSH6 and PMS2 within Lynch syndrome. Indications for its investigation currently remain limited to patients with a clinical suspicion for sporadic UTUC to refer only those with a positive testing for germline DNA sequencing to screen for this syndrome. With regard to technical aspects, despite the interest of MSIsensor, only PCR and immunohistochemistry are routinely used to somatically investigate the MSI and dMMR phenotypes, respectively. The prevalence of the MSI/dMMR phenotype in UTUC patients ranges from 1.7% to 57%, depending on the study population, investigation method and definition of a positive test. Younger age and a more balanced male to female ratio at initial diagnosis are the main specific clinical characteristics of UTUC patients with an MSI/dMMR phenotype. Despite the conflicting results available in the literature, these patients may have a better prognosis, potentially related to more favourable pathological features. Finally, they may also have lower sensitivity to chemotherapy but greater sensitivity to immunotherapy.

CONCLUSION

Our collaborative review summarises the available data from published studies exploring the MSI/dMMR phenotype in UTUC patients, the majority of which are limited by a low level of evidence.

Clinicopathological outcomes of microsatellite instability in colorectal cancer

AIMS

This study aims to evaluate the histopathological features and prognostic parameters of tumors with microsatellite instability (MSI) compared with those without MSI in patients who underwent surgery for colorectal cancer (CRC).

SETTING AND DESIGN

Follow-up for CRC at Istanbul Sultan 2. Abdulhamid Han Training and Research Hospital was retrospectively evaluated between March 2017 and March 2021.

METHODS AND MATERIAL

The patients were divided into two groups: those with and without MSI. Groups were compared in survival parameters. As a secondary result, groups were compared in pathological parameters such as stage, tumor diameter, degree of differentiation, and lymphovascular, and perineural invasion.

STATISTICAL ANALYSIS USED

Survival calculations were performed using the Kaplan-Meier analysis method. The effects of various prognostic factors related to tumor and patient characteristics on disease-free and overall survival (OS) were investigated by log-rank test.

RESULTS

Two hundred fourteen patients were analyzed. The median age of the patients was 66 (30-89), and 59.3% (n = 127) were male. There were 25 patients in the MSI group and 189 patients in the non-MSI group. We found that MSI tumors had a significantly higher differentiation degree than non-MSI tumors and larger tumor diameters. MSI tumors frequently settled in the proximal colon, and more lymph nodes were removed in the resection material. MSI tumors had longer disease-free survival, cancer-specific survival, and overall survival.

CONCLUSIONS

By diagnosing microsatellite instability, CRCs can be divided into two groups. The histopathological features of the tumor and the prognosis of the disease differ between these groups. MSI can be a predictive marker in the patient's follow-up and treatment.

Immunoexpression of Mismatch Repair Proteins in a Cohort of Colorectal Cancer Patients

One of the molecular routes of colorectal carcinogenesis is the lack of mismatch repair (MMR) proteins, which may have substantial clinical consequences in predicting therapy success. This study aimed to analyze the expression of the MutL homolog 1 (MLH1), MutS homolog 2 (MSH2), and MutS homolog 6 (MSH6) in a cohort of 91 colorectal cancer (CRC) patients, and to evaluate the relationship between patient clinicopathological characteristics and immunoexpression of these biomarkers. In this study, we obtained the highest scores of the MLH1 immunoexpression in non-mucinous tumors, moderately differentiated lesions, and in stage IV. The highest values of the MSH2 and MSH6 scores were observed in mucinous tumors, and poorly differentiated lesions, in stages II-III, and stages III-IV, respectively. To improve the stratification criteria for targeted oncological therapy and to predict patient outcomes, markers used may help evaluate the aggressiveness of lesions.

MSI colorectal cancer, all you need to know

Colorectal cancer management has been dramatically impacted by molecular profiling these last years. Among these molecular subgroups, patients with microsatellite instability (MSI) are of particular interest, owing to the prognostic and predictive value of this tumor biomarker. This review article explains the molecular abnormalities underlying MSI phenotype and the consequences of such molecular abnormalities on carcinogenesis, genetic instability and immune infiltration. It details the diagnostic methods for identifying MSI colorectal cancer patients and describes how the prognostic and theranostic values of this marker are impacting treatment decision-making for these patients in 2022.

Rate of dissemination and prognosis in early and advanced stage colorectal cancer based on microsatellite instability status: systematic review and meta-analysis

INTRODUCTION

For the past two decades, microsatellite instability (MSI) has been reported as a robust clinical biomarker associated with survival advantage attributed to its immunogenicity. However, MSI is also associated with high-risk adverse pathological features (poorly differentiated, mucinous, signet cell, higher grade) and exhibits a double-edged sword phenomenon. We performed a systematic review and meta-analysis to evaluate the rate of dissemination and the prognosis of early and advanced stage colorectal cancer based on MSI status.

METHODS

A systematic literature search of original studies was performed on Ovid searching MEDLINE, Embase, Cochrane Database of Systematic Reviews, American College of Physicians ACP Journal Club, Database of Abstracts of Reviews of Effects DARE, Clinical Trials databases from inception of database to June 2019. Colorectal cancer, microsatellite instability, genomic instability and DNA mismatch repair were used as key words or MeSH terms. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed. Data were pooled using a random-effects model with odds ratio (OR) as the effect size. Statistical analysis was performed using RevMan ver 5.3 Cochrane Collaboration.

RESULTS

From 5288 studies, 136 met the inclusion criteria (n = 92,035; MSI-H 11,746 (13%)). Overall, MSI-H was associated with improved OS (OR, 0.81; 95% CI 0.73-0.90), DFS (OR, 0.73; 95% CI 0.66-0.81) and DSS (OR, 0.69; 95% CI 0.52-0.90). Importantly, MSI-H had a protective effect against dissemination with a significantly lower rate of lymph node and distant metastases. By stage, the protective effect of MSI-H in terms of OS and DFS was observed clearly in stage II and stage III. Survival in stage I CRC was excellent irrespective of MSI status. In stage IV CRC, without immunotherapy, MSI-H was not associated with any survival benefit.

CONCLUSIONS

MSI-H CRC was associated with an overall survival benefit with a lower rate of dissemination. Survival benefit was clearly evident in both stage II and III CRC, but MSI-H was neither a robust prognostic marker in stage I nor stage IV CRC without immunotherapy.

Assessment of mismatch repair deficiency, CDX2, beta-catenin and E-cadherin expression in colon cancer: molecular characteristics and impact on prognosis and survival - an immunohistochemical study

Microsatellite instability (MSI) or the deficiency of mismatch repair (MMR) proteins is one of the molecular pathways of colorectal tumorigenesis and may have important clinical implications in predicting the treatment response. We evaluated the relationship between clinicopathological features and MMR proteins [mutL homologue 1 (MLH1), mutS homologue 2 (MSH2), mutS homologue 6 (MSH6), postmeiotic segregation increased 2 (PMS2)], adhesion molecules (E-cadherin, beta-catenin) and caudal-type homeobox 2 (CDX2) in 31 patients with colon adenocarcinoma, using immunohistochemistry. We also aimed to assess the prognostic value of the studied proteins. MLH1 loss was correlated to PMS2 loss (p=0.006) and MSH2 loss (p=0.023); MSH2 loss was significantly associated to MSH6 loss (p=0.011). Tumors with MSH6 loss, together with tumors with PMS2 loss, covered all the patients with MSI status. We found a significant correlation between MSI tumors and mucinous histological type (p=0.03), but no significant associations with other clinicopathological features or with survival rate. There was a significant correlation between E-cadherin expression and differentiation degree (p=0.018) and between beta-catenin expression and lymph node invasion (p=0.046). No significant association between CDX2 loss and any clinical or pathological features was found (p>0.05). No significant differences were identified in overall survival according to E-cadherin, beta-catenin or CDX2 expression (p>0.05). In our study, PMS2 loss was significantly correlated with CDX2 loss (p=0.03). In conclusion, the molecular analysis of biological markers for colon cancer may be important for patient stratification, in order to select the optimal treatment algorithm. Our results suggest that probably the double panel (MSH6 and PMS2) is enough to detect the MSI status, instead of using the quadruple panel.

Tumor-derived mutations in postoperative plasma of colorectal cancer with microsatellite instability

The mutation in postoperative plasma (molecular residues) was an independently prognostic factor in colorectal cancer (CRC). The status of postoperative plasma mutation of microsatellite instability (MSI) CRC has not been systematically examined. In this study, we enrolled 30 MSI and 46 microsatellite stability (MSS) CRCs, and performed next generation sequencing on surgical tissues, postoperative plasma, and plasma during follow-up. Compared with MSS, MSI tumors had dissimilar genomic profiles, higher tumor mutation burden (TMB), and more frameshift mutations. In the postoperative plasma, more MSI CRCs were detected with tumor-derived mutations (77% in MSI vs 33% in MSS, p < 0.001). The numbers of postoperative mutations were proportional to MSI tissues (Spearman r = 0.47, p = 0.023), while not for MSS. More proportion of postoperative plasma samples of MSI CRCs harbored frameshift mutations than MSS (p = 0.007). For the follow-up plasma, 93% (14 out of 15) MSI CRCs harbored tumor-derived mutations; 33% (4/12) MSS were mutation-positive, lower than MSI (p = 0.003). Thus, considering that MSI CRC had extremely distinct mutational characteristics in tumor and postoperative plasma compared with MSS CRC, we propose that the prognostic value of molecular residue identification in postoperative plasma needs to be independently evaluated in MSI and MSS CRCs.

Mismatch Repair System Deficiency Is Associated With Response to Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

PURPOSE

Defective mismatch repair system (dMMR) has been shown to have a favorable impact on outcome in patients with colorectal cancer treated with surgery or immunotherapy, with adjuvant chemotherapy being discouraged unless there is nodal involvement. Its impact on radiosensitivity is unknown in patients with colorectal cancer.

METHODS AND MATERIALS

Patients treated for locally advanced rectal cancer between 2000 and 2016 were studied. Reported points included age, sex, clinical and radiologic tumor stages at diagnosis, modalities of neoadjuvant treatment, posttreatment pathologic staging, tumor regression score, and local, distant relapse-free, and overall survival. An inverse probability of treatment weighting propensity score analysis was performed to evaluate the association of mismatch repair proficiency with surgical and clinical outcomes.

RESULTS

Among the 296 patients included, 23 (7.8%) had dMMR. Median follow-up was 43.0 months (interquartile range, 27.9-66.7). Patients with dMMR were significantly younger than the others. After inverse probability of treatment weighting propensity score matching, dMMR patients had higher pathologic downstaging rate (P < .0001), higher tumor regression grade (P = .024), and a longer recurrence-free survival (P < .0001).

CONCLUSIONS

dMRR was associated with significant tumor downstaging after neoadjuvant chemoradiation and with increased recurrence-free survival. dMMR patients may have more radiosensitive tumors.

Cancer molecular markers: A guide to cancer detection and management

Cancer is generally caused by the molecular alterations which lead to specific mutations. Advances in molecular biology have provided an impetus to the study of cancers with valuable prognostic and predictive significance. Over the hindsight various attempts have been undertaken by scientists worldwide, in the management of cancer; where, we have witnessed a number of molecular markers which allow the early detection of cancers and lead to a decrease in its mortality rate. Recent advances in oncology have led to the discovery of cancer markers that has allowed early detection and targeted therapy of tumors. In this context, current review provides a detail outlook on various molecular markers for diagnosis, prognosis and management of therapeutic response in cancer patients.

Adjuvant Chemotherapy for Stage II and III Colon Cancer Following Complete Resection: A Cancer Care Ontario Systematic Review

The objective of this systematic review was to provide current evidence regarding the use of adjuvant systemic chemotherapy for stage II and III colon cancer following curative intent surgery. MEDLINE and EMBASE databases and proceedings of American Society for Clinical Oncology and European Society of Medical Oncology/European Cancer Congress were searched through to August 2015. Systematic reviews (with or without meta-analyses) and randomised controlled trials were included. Patients with completely resected stage III colon cancer have an overall survival benefit from adjuvant chemotherapy. Combination chemotherapy (5-fluorouracil/leucovorin/oxaliplatin or capecitabine/oxaliplatin) provides a larger benefit than monotherapy but with additional toxicity. For stage II colon cancer, a clear overall survival benefit has not been shown. However, based on the subgroup analysis available, patients with high-risk stage II disease may benefit from adjuvant chemotherapy. Patients younger than 70 years of age may derive greater disease-free survival and overall survival benefit from adjuvant chemotherapy (in combination with oxaliplatin) compared with those older than 70 years. Stage II patients with microsatellite instability may have an overall survival detriment if given adjuvant chemotherapy.

IGFBP-3 Gene Methylation in Primary Tumor Predicts Recurrence of Stage II Colorectal Cancers

OBJECTIVES

To evaluate the influence of IGFBP-3 methylation on recurrence in patients with stage II colorectal cancer (CRC) from 2 independent cohorts.

BACKGROUND

The relationship between IGFBP-3 methylation in primary tumors (PTs) or lymph nodes (LNs) and risk of recurrence in patients with stage II CRC treated with surgery alone is unknown.

METHODS

IGFBP-3 methylation of DNA from 115 PTs and 1641 LNs in patients with stage II CRC from 2 independent cohorts was analyzed. Forty patients developed recurrence, whereas 75 matched patients remained recurrence free for more than 2 years after surgery. Cox proportional hazard models were used to calculate hazard ratios (HRs) of recurrence, adjusted for patient and tumor characteristics.

RESULTS

Methylation of IGFBP-3 in PTs was identified to be significantly associated with risk of recurrence in the training set. The signature was tested in a validation set and classified 40.7% of patients as high risk. Five-year recurrence-free survival rates were 76.4% and 58.3% for low- and high-risk patients, respectively, with an HR of 2.21 (95% confidence interval, 1.04-4.68; P = 0.039). In multivariate analysis, the signature remained the most significant prognostic factor, with an HR of 2.40 (95% confidence interval, 1.10-5.25; P = 0.029). A combined analysis of 1641 LNs from the 2 sets identified IGFBP-3 methylation in LNs was not associated with risk of recurrence.

CONCLUSIONS

Detection of IGFBP-3 methylation in PTs, but not in LNs, provides a powerful tool for the identification of patients with stage II CRC at high risk of recurrence.

Histone modifiers and marks define heterogeneous groups of colorectal carcinomas and affect responses to HDAC inhibitors in vitro

Little is known about histone modifiers and histone marks in colorectal cancers (CRC). The present study therefore addressed the role of histone acetylation and histone deacetylases (HDAC) in CRCs in situ and in vitro. Immunohistochemistry of primary CRCs (n=47) revealed that selected histone marks were frequently present (H3K4me3: 100%; H3K9me3: 77%; H3K9ac: 75%), partially displayed intratumoral heterogeneity (H3K9me3; H3K9ac) and were significantly linked to higher pT category (H3K9me3: p=0.023; H3K9ac: p=0.028). Furthermore, also HDAC1 (62%), HDAC2 (100%) and HDAC3 (72%) expression was frequent, revealing four CRC types: cases expressing 1) HDAC1, HDAC2 and HDAC3 (49%), 2) HDAC2 and HDAC3 (30%), 3) HDAC1 and HDAC2 (10.5%) and 4) exclusively HDAC2 (10.5%). Correlation to clinico-pathological parameters (pT, pN, G, MSI status) revealed that heterogeneous HDAC1 expression correlated with lymph node status (p=0.012). HDAC expression in situ was partially reflected by six CRC cell lines, with similar expression of all three HDACs (DLD1, LS174T), preferential HDAC2 and HDAC3 expression (SW480, Caco2) or lower HDAC2 and HDAC3 expression (HCT116, HT29). HDAC activity was variably higher in HCT116, HT29, DLD1 and SW480 compared to LS174T and Caco2 cells. Treatment with broad (SAHA) and specific (MS-275; FK228) HDAC inhibitors (HDACi) caused loss of cell viability in predominantly MSIpositive CRC cells (HCT116, LS174T, DLD1; SAHA, MS-275 and in part FK228). In contrast, MSI-negative CRC cells (Caco2, HT29, SW480) were resistant, except for high doses of FK228 (Caco2, HT29). Cell viability patterns were not linked to different efficacies of HDACi on reduction of HDAC activity or histone acetylation, p21 expression and/or induction of DNA damage (γH2A-X levels). In summary, this study reveals inter- and intra-tumoral heterogeneity of histone marks and HDAC expression in CRCs. This is reflected by diverse HDACi responses in vitro, which do not follow known modes of action. Together, this implies further exploitation of histone alterations in CRC for molecular classification and/or novel treatment options.

Molecular biomarkers in colorectal carcinoma

Colorectal cancer is a tumor with increasing incidence which represents one of the first leading causes of death worldwide. Gene alterations described for colorectal cancer include genome instability (microsatellite and chromosomal instability), CpG islands methylator phenotype, microRNA, histone modification, protein biomarkers, gene mutations (RAS, BRAF, PI3K, TP53, PTEN) and polymorphisms (APC, CTNNB1, DCC). In this article, biomarkers with prognostic value commonly found in colorectal cancer will be reviewed.

[Colorectal carcinoma in consideration of the new German S3 guideline 2013]

In the current German S3 guidelines for colorectal carcinoma (CRC), morphologically based tumor grading is extended by molecular grading for poorly differentiated and undifferentiated carcinomas, as well as for special morphological subtypes. These CRC are classified as low-grade when microsatellite instability (MSI) is found. In routine diagnostics, immunohistochemistry for hMLH1 and hMSH2, capturing MSI-CRC with high sensitivity and specificity, can be used as an inexpensive substitute for molecular MSI-testing. In patients with positive Bethesda criteria, a stepwise immunohistochemical and molecular diagnostic scheme is proposed. The detection of a BRAF mutation in tumors with hMLH1 loss allows distinguishing between sporadic and HNPCC-associated MSI-CRC. For rectal cancer the residual tumor classification (R-status) is completed by the circumferential resection margin classification (CRM).

Should mismatch repair status be determined in all stage II and III colon cancer patients?

SUMMARY 

Microsatellite instability constitutes an important oncogenic molecular pathway in colon cancer (12–15%). Microsatellite instability is a molecular marker of deficient DNA mismatch repair (MMR), which occurs from somatic hypermethylation of the MLH1 promoter or less frequently as a result of germline mutations in MMR genes. The excellent prognosis of patients with stage II deficient MMR colon cancer today, makes this information mandatory in order to decide or not on adjuvant chemotherapy. MMR deficiency may also predict tumor chemoresistance to 5-fluorouracil adjuvant treatment. However, when looking at very recent data on 5-fluorouracil plus oxaliplatin-based adjuvant regimens, it seems that the benefit of this adjuvant therapy is similar between deficient and proficient MMR patients.

Oncologic results after multivisceral resection of clinical T4 tumors

BACKGROUND

Standard operative management of colorectal cancer (CRC) with adherent adjacent organs is en bloc resection to obtain clear resection margins. We analyzed early and long-term outcomes after multivisceral resection for clinically suspected T4 CRC and identified factors predicting survival.

METHODS

All patients operated on for clinically suspected T4 CRC between 2000 and 2010 were identified retrospectively. Data concerning demographics, surgery, pathologic examination and oncologic outcome were analyzed.

RESULTS

One hundred fifty-two patients underwent partial or total en bloc resection of ≥1 adherent organ. An R0 resection was achieved in 136 patients (89.5%). Malignant invasion of the adherent organ was histologically confirmed in 98 patients (64.5%). Five-year overall survival and disease-free survival rates were 77.4% and 58.1%, respectively. On univariate analysis, margin positivity, pT4 stage, and lymph node invasion were predictors of a worse disease-free survival. The presence of liver metastases and concomitant hepatectomy were both factors of poor overall and disease-free survival. On multivariate analysis, resection of ≥2 adjacent organs was a predictor of better overall survival. This finding may be explained by the significantly higher rate of tumors with microsatellite instability (MSI) in the group with resection of multiple organs.

CONCLUSION

The oncologic outcome of multivisceral resection for clinically suspected colorectal T4 tumors was good, especially in MSI patients and patients without liver metastases. The number of organs requiring resection should not contraindicated radical surgery as in this study it was associated with a good prognosis.

Biomarkers in precision therapy in colorectal cancer

Colorectal cancer (CRC) is the most commonly diagnosed cancer in Europe. Because CRC is also a major cause of cancer-related deaths worldwide, a lot of research has been focused on the discovery and development of biomarkers to improve the diagnostic process and to predict treatment outcomes. Up till now only a few biomarkers are recommended by expert panels. Current TNM criteria, however, cause substantial under- and overtreatment of CRC patients. Consequently, there is a growing need for new and efficient biomarkers to ensure optimal treatment allocation. An ideal biomarker should be easily translated into clinical practice, to identify patients who can be spared from treatment or benefit from therapy, ultimately resulting in precision medicine in the future. In this review we aim to provide an overview of a number of frequently studied biomarkers in CRC and, at the same time, we will emphasize the challenges and controversies that withhold the clinical introduction of these biomarkers. We will discuss both prognostic and predictive markers of chemotherapy, aspirin therapy as well as overall therapy toxicity. Currently, only mutant KRAS, mutant BRAF, MSI and the Oncotype DX® Colon Cancer Assay are used in clinical practice. Other biomarker studies showed insufficient evidence to be introduced into clinical practice. Divergent patient selection criteria, absence of validation studies and a large number of single biomarker studies are possibly responsible. We therefore recommend that future studies focus on combining key markers, rather than analysing single markers, standardizing study protocols, and validate the results in independent study cohorts, followed by prospective clinical trials.

Poor prognosis of KRAS or BRAF mutant colorectal liver metastasis without microsatellite instability

BACKGROUND

The discovery of practical biomarkers is important to realize personalized medicine for patients with malignant neoplasias, including colorectal cancer (CRC).

PURPOSE

The aim of this study was to determine reliable prognostic biomarkers by the analysis of patients with resectable colorectal liver metastases (CRLM).

METHODS

Genomic DNA was obtained from the CRLM tissues of a cohort of 126 patients with CRLM with curative hepatic resection. The KRAS/BRAF mutation spectrum and microsatellite instability (MSI) status were successfully analyzed in 100 of the 126 CRLM tissues and these findings were examined in relation to the patients' clinical outcomes.

RESULTS

The cohort of 100 CRLM patients consisted of 46 with synchronous and 54 with metachronous liver metastasis. Overall survival and disease-free survival at 5 years were 57.4 and 24.9 %, respectively. MSI analysis revealed that none of the 100 CRLM specimens showed any evidence of MSI. By KRAS/BRAF mutation analysis, the analyzed CRLM patients were divided into 3 groups; KRAS-mutant (KRAS-Mt; n = 27), BRAF-mutant (BRAF-Mt; n = 3), and wild-types of both genes (Wild-type; n = 70). In the survival analysis, both KRAS-Mt and BRAF-Mt patients showed significantly poorer prognoses compared with Wild-type patients. Furthermore, although the population with the BRAF mutation was small, this mutation had a significant negative impact on disease-free survival.

CONCLUSIONS

In this study, all tumors in the cohort of CRLM patients were non-MSI tumors, suggesting MSI cancer in primary CRC would rarely reveal metastatic potential. KRAS and BRAF mutations are suggested to be poor prognostic factors in CRLM. Genetic information has an essential role as a prognostic marker and could contribute to the decisions on treatment strategy for CRLM.

Linear quantification of lymphoid infiltration of the tumor margin: a reproducible method, developed with colorectal cancer tissues, for assessing a highly variable prognostic factor

Background

Lymphoid infiltration is a prognostic marker in solid tumors, such as colorectal, breast and lung carcinomas. However, lymphoid infiltration is heterogeneous and the reproducibility of quantification based on single counts within a tumor is very low. We aimed to develop a reproducible method for evaluating lymphoid infiltration in tumors.

Methods

Virtual slides were obtained from tissue sections from the localized colorectal carcinomas of 117 patients, stained for CD3 and CD45R0. We assessed the variation of lymphoid cell density by automatic counts in 1 mm-wide, 5 μm-long segments of the invasive front, along an axis 4 mm in length running perpendicular to the invasive front of the tumor.

Results

We plotted curves of the variation of lymphocyte density across the tumor front. Three distinct patterns emerged from this linear quantification of lymphocyte (LQLI). In pattern 1, there was a high density of lymphocytes within the tumor. In pattern 2, lymphocyte density peaked close to the invasive margin. In pattern 3, lymphocytes were diffusely distributed, at low density. It was possible to classify all the tumors studied, and interobserver reproducibility was excellent (kappa =0.9). By contrast, single counts of CD3⁺ cells on tissue microarrays were highly variable for a given LQLI pattern, confirming the heterogeneity of lymphoid infiltration within individual tumors. In univariate analysis, all pathologic features (stage, metastatic lymph node ratio (LNR), vascular embolism, perineural invasion), CD3⁺ cell density, LQLI patterns for CD3⁺ and CD45R0⁺ cells) were found to have a significant effect on disease-free survival (DFS). In multivariate analysis, only the LQLI pattern for CD3⁺ cells (HR: 6.02; 95% CI: 2.74-13.18) and metastatic lymph node ratio (HR: 6.14; 95% CI: 2.32-16.2) were associated with DFS.

Conclusion

LQLI is an automated, reproducible method for the assessment of lymphoid infiltration. However, validation of its prognostic value in larger series is required before its introduction into routine practice for prognostic evaluation in patients with colorectal carcinomas.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9861460717895880

Multimodal treatment strategies for locally advanced rectal cancer

This review outlines the important multimodal treatment issues associated with locally advanced rectal cancer. Changes to chemotherapy and radiation schema, as well as modern surgical approaches, have led to a revolution in the management of this disease but the morbidity and mortality remains high. Adequate treatment is dependent on precise preoperative staging modalities. Advances in staging via endorectal ultrasound, computed tomography, MRI and PET have improved pretreatment triage and management. Important prognostic factors and their impact for this disease are under investigation. Here we discuss the different treatment options including modern tumor-related surgical approaches, neoadjuvant as well as adjuvant therapies. Further clinical progress will largely depend on the broader implementation of multidisciplinary treatment strategies following the principles of evidence-based medicine.

An alternative pathway in colorectal carcinogenesis based on the mismatch repair system and p53 expression in Korean patients with sporadic colorectal cancer

PURPOSE

Microsatellite instability (MSI) and chromosomal instability are main mechanisms underlying colorectal carcinogenesis. We determined the features and prognosis of colorectal cancer based on MSI including mismatch repair genes and expression of p53.

METHODS

Between 1999 and 2008, a total of 2,649 colorectal cancer patients were analyzed using a prospective database. A mismatch repair defect (MMR-D) was defined as a loss of expression of more than one MMR protein and/or MSI-high. MMR-proficiency (MMR-P) was defined as expression of all MMR proteins and microsatellite stable (MSS)/MSI-low. Groups 1 (G1), 2 (G2), 3 (G3), and 4 (G4) were defined as MMR-D and p53-positive expression, MMR-D and p53-negative expression, MMR-P and p53-positive expression, MMR-P and p53-negative expression, respectively.

RESULTS

Eighty-two (3.0%), 181 (6.8%), 1,368 (51.7%), and 1,018 (38.5%) patients were classified into groups 1-4, respectively. Comparison between G1 and G2 showed differences in location (p < 0.001), size (p = 0.030), node metastasis (p = 0.027), distant metastasis (p = 0.009), and stage (p = 0.040). Comparison between G3 and G4 showed differences in location (p < 0.001) and histology (p < 0.001). Comparison between G1 and G3 showed differences in location (p < 0.001) and histology (p < 0.001). Comparison between G2 and G4 showed differences in age (p < 0.001), location (p < 0.001), size (p = 0.006), histology (p < 0.001), node metastasis (p < 0.001), distant metastasis (p < 0.001), and stage (p < 0.001). On multivariate analysis, stage (p = 0.007) and histology (p < 0.001) were associated with improved overall survival, and stage (p < 0.001) was associated with disease-free survival.

CONCLUSIONS

According to the MSI and p53 subsets, colorectal cancers showed different clinicopathologic features, but these subsets had no prognostic impact on overall and disease-free survival rate.

High lymph node yield is related to microsatellite instability in colon cancer

BACKGROUND

Lymph node (LN) yield in colon cancer resection specimens is an important indicator of treatment quality and has especially in early-stage patients therapeutic implications. However, underlying disease mechanisms, such as microsatellite instability (MSI), may also influence LN yield, as MSI tumors are known to exhibit more prominent lymphocytic antitumor reactions. The aim of the present study was to investigate the association of LN yield, MSI status, and recurrence rate in colon cancer.

METHODS

Clinicopathological data and tumor samples were collected from 332 stage II and III colon cancer patients. DNA was isolated and PCR-based MSI analysis performed. LN yield was defined as "high" when 10 or more LNs were retrieved and "low" in case of fewer than 10 LNs.

RESULTS

Tumors with high LN yield were significantly associated with the MSI phenotype (high LN yield: 26.3% MSI tumors vs low LN yield: 15.1% MSI tumors; P=.01), mainly in stage III disease. Stage II patients with high LN yield had a lower recurrence rate compared with those with low LN yield. Patients with MSI tumors tended to develop fewer recurrences compared with those with MSS tumors, mainly in stage II disease.

CONCLUSIONS

In the present study, high LN yield was associated with MSI tumors, mainly in stage III patients. Besides adequate surgery and pathology, high LN yield is possibly a feature caused by biologic behavior of MSI tumors.

Clinical decision aids in colon cancer: a comparison of two predictive nomograms

BACKGROUND

The risk of recurrence of colon cancer after curative surgery can be estimated by using decision aids. These aids use pathologic and patient factors to predict recurrence risk after adjuvant chemotherapy and have been validated when using clinical trial populations; however, the performance of 2 decision aids were compared by using a cohort of patients treated at a single center.

PATIENTS AND METHODS

Patient data were used to estimate the risk of recurrence when using both the Adjuvant! for colon cancer and Memorial Sloan Kettering Cancer Center (MSKCC) decision aids. A receiver operator characteristic (ROC) curve analyzed the predicted chance of being disease free at 5 years against the actual outcome for each patient. This curve was then used to define cutoff points at a chosen sensitivity and specificity to stratify patients into risk groups, and survival curves for each group calculated.

RESULTS

Data on 134 patients were analyzed. The Pearson correlation between the 2 nomograms was 0.848 (P < .01). The ROC curve for the MSKCC nomogram had an area under the curve of 0.638. At a sensitivity and a specificity of 0.8, the MSKCC curve has a risk recurrence score of 69% and 84%, respectively. By using these cutoffs to stratify patients into 3 risk groups, a statistically significant difference in survival was found between high risk and low risk (P = .025).

CONCLUSION

Tools to predict risk or recurrence and estimate benefit from therapy may be enhanced in the future by using genetic profiling, but use of existing tools can help deliver a personalized approach to adjuvant therapy.

Pathways of carcinogenesis are reflected in patterns of polyp pathology in patients screened for colorectal cancer

BACKGROUND

There are multiple genetic routes to colorectal cancer, including chromosomal instability, mismatch repair dysfunction, and global hypermethylation. Few consider the possibility that multiple pathways are synchronously active.

OBJECTIVE

This study was conducted to test the hypothesis that multiple synchronous carcinogenic pathways would result in an enhanced neoplastic phenotype.

SETTING

This study took place during outpatient screening colonoscopy.

PATIENTS

Patient were included who were undergoing colonoscopies for average and familial risk for colorectal cancer.

DESIGN

Adenomas were evidence of chromosomal instability or DNA mismatch repair dysfunction, and serrated polyps of CpG island hypermethylation. Patients with 1 or 2 polyps were compared with those with >2 polyps, with polyps more than 10-mm diameter (advanced) as the end point.

RESULTS

There were 1408 patients: 524 at average risk (41%) and 884 (59%) with a family history. Polyps were found in 47.7% of the average-risk patients and in 45.9% of patients with a family history. Adenoma detection rates were 33.8% and 30.4%, and serrated polyp detection rates were 24.8% and 23.9%. There were more advanced polyps in all patients with >2 polyps than in those with 1 or 2 (36.2% vs 13.6%, P < .002), as well as in the subgroup of patients having average-risk screening (50% vs 11.1%, P < .001). Having a combination of >2 adenomas and serrated polyps in the same colon increased the risk of finding advanced polyps compared with adenomas or serrated polyps alone (serrated polyps, 12.7%; >2 adenomas, 17.7%; both, 27.1%; P = .02).

LIMITATIONS

Serrated polyps were not subclassified by histology.

CONCLUSION

Coexistence of serrated and adenomatous polyps reflects a colon prone to advanced polyps, and potentially cancer.

Screening for Lynch syndrome in colorectal cancer: are we doing enough?

PURPOSE

The purpose of this study was to assess the efficacy of screening for the detection of Lynch syndrome (LS) in an unselected population undergoing surgery for a colorectal cancer.

METHODS

A total of 1,040 patients were prospectively included between 2005 and 2009. LS screening modalities included the Bethesda criteria, immunochemistry (IHC) for MLH1, MSH2, and MSH6, and microsatellite instability (MSI) by using pentaplex markers. Promoter methylation was assessed in tumors with a loss of MLH1 expression. Gene sequencing was offered to patients with abnormal IHC or MSI status without promoter methylation.

RESULTS

A total of 105 patients had an abnormal result: 102 (9.8%) exhibited a loss of protein on IHC and 98 (9.4%) had MSI. A discordant result was observed in 10 patients with eventual proven LS in 6 patients. Loss of MLH1 (n = 64) was due to promoter methylation in 43 patients (67.2%). Overall, of 62 patients with an abnormal result, 38 had genetic sequencing leading to 25 (65.8%) identified with a germ-line mutation. Loss of MSH2 on IHC was associated with a mutation in 78.3% (18 of 23) of cases. Among the 62 patients with abnormal results, 23 (37.1%) did not meet the Bethesda criteria.

CONCLUSIONS

Strict application of the Bethesda criteria does not lead to identification of all patients with LS. IHC and MSI testing are complementary methods and should be used in association to identify potential LS patients.

Adjuvant Chemotherapy for Stage II Colon Cancer: The Role of Molecular Markers in Choosing Therapy

The optimal adjuvant treatment for stage II colon cancer remains controversial. While chemotherapy is often recommended for high-risk stage II disease, many low-grade tumors with similar histopathologic features will recur and ultimately cause cancer-associated mortality. The development of molecular markers that predict clinical outcome or response to therapy in stage II colon cancer is an important tool that could give clinicians added information in discussions regarding the role of adjuvant chemotherapy. While many potential molecular biomarkers have been investigated, to date none have been validated in prospective clinical trials. Among the most promising molecular markers to be studied are microsatellite instability and 18q and 17p loss of heterozygosity, both of which are currently being evaluated as prognostic indicators in a large prospective clinical trial (Eastern Cooperative Oncology Group 5202). This review focuses on potential molecular biomarkers being evaluated for their prognostic value in stage II colon cancer and their potential role in clinical decision-making regarding the use of adjuvant chemotherapy.

[HNPCC (hereditary non-polyposis colorectal cancer) or Lynch syndrome: a syndrome related to a failure of DNA repair system]

The HNPCC syndrome (hereditary non polyposis colon cancer) or Lynch syndrome stands for an autosomic dominant condition leading to the most prevalent hereditary colo-rectal cancers (CCR). MMR (mismatch repair)'s genes are involved in carcinogenesis as they play a role in ADNA mismatch repair. Microsatellite instability (MSI+ phenotype) induced by germline mutations is characteristic of such tumors and is necessary to assert the diagnosis. The HNPCC syndrome is associated with a significant increased risk of CCR altogether with endometrium, upper urinary tract and small bowel carcinomas as well as ovarian, biliary system and gastric cancers although of lesser extent. It is of importance to diagnose HNPCC syndrome prior to the treatment starts because it may influence patient's (as well as her/his relatives) disease management (type of surgery, surveillance and screening exams). New French recommendations, developed in 2009, about prophylactic colo-rectal and gynecologic surgeries and monitoring update latest ones published on 2004.

MYH biallelic mutation can inactivate the two genetic pathways of colorectal cancer by APC or MLH1 transversions

MYH associated polyposis is a hereditary syndrome responsible for early colorectal cancer with a distinct genetic pathway from the Familial Adenomatous Polyposis or the Hereditary Non Polyposis Colorectal Cancer syndrome. We have studied a family with three members bearing a biallelic mutation in MYH at c.1185_1186dup. One patient who developed colon cancer had loss of expression of MLH1 on tumoral tissue and microsatellite instability (MSI) phenotype. Analysis of MLH1 based on his blood sample revealed no germline mutation or large genomic deletion. No methylation of the promoter was identified in tumoral DNA. No transversion mutations were identified in APC or KRAS in tumor DNA of this patient. Loss of expression of MLH1 was due to a transversion in intron 7 at position +5 (c.588 + 5G > T) leading to a complete deletion of exon 7 at the RNA level. This observation demonstrates that MLH1 can be a target of MYH transversions leading to MSI phenotype.

Absence of hMLH1 or hMSH2 expression as a stage-dependent prognostic factor in sporadic colorectal cancers

BACKGROUND

The predictive role of mismatch repair (MMR) status for survival after sporadic colorectal cancer remains a point of controversy. This study was designed to test the prognostic value of MMR status in sporadic colorectal cancers.

METHODS

The study included 318 patients with sporadic colorectal cancer who underwent primary tumor resection. MMR status was determined by the immunohistochemical analysis of hMLH1 and hMSH2 expression.

RESULTS

Thirty-six carcinomas (11.3%) showed abnormal MMR protein expression (22 hMLH1 negative and 14 hMSH2 negative) and were classified as MMR-defective tumors. An MMR defect was strongly associated with a reduced likelihood of lymph node (odds ratio, 0.32; 95% confidence interval [95% CI], 0.13-0.75) or distant organ metastases at diagnosis (odds ratio, 0.07; 95% CI, 0.01-0.62), independent of the clinicopathological features. Overall survival was significantly better in patients with MMR-defective tumors than in those with MMR-intact tumors (P = 0.013). In the subgroup analysis by stage, adjusted for other potential confounding variables, MMR status was not a statistically significant prognostic factor in stage I and II patients, while the MMR defect predicted a significantly better overall survival in stage III and IV patients (adjusted hazard ratio, 0.23; 95% CI, 0.06-0.97; P = 0.045).

CONCLUSIONS

At initial diagnosis, metastases were found at lower rates in MMR-defective tumors. MMR status may be a stage-dependent prognostic factor in patients with sporadic colorectal cancer.

Microsatellite instability in colorectal cancer

Microsatellite instability (MSI) is a hypermutable phenotype caused by the loss of DNA mismatch repair activity. MSI is detected in about 15% of all colorectal cancers; 3% are of these are associated with Lynch syndrome and the other 12% are caused by sporadic, acquired hypermethylation of the promoter of the MLH1 gene, which occurs in tumors with the CpG island methylator phenotype. Colorectal tumors with MSI have distinctive features, including a tendency to arise in the proximal colon, lymphocytic infiltrate, and a poorly differentiated, mucinous or signet ring appearance. They have a slightly better prognosis than colorectal tumors without MSI and do not have the same response to chemotherapeutics. Discovery of MSI in colorectal tumors has increased awareness of the diversity of colorectal cancers and implications for specialized management of patients.

MAL promoter hypermethylation as a novel prognostic marker in gastric cancer

T-lymphocyte maturation associated protein, MAL, has been described as a tumour-suppressor gene with diagnostic value in colorectal and oesophageal cancers, and can be inactivated by promoter hypermethylation. The aim of this study was to analyse the prevalence of MAL promoter hypermethylation and the association with mRNA expression in gastric cancers and to correlate methylation status to clinicopathological data. Bisulphite-treated DNA isolated from formalin-fixed and paraffin-embedded samples of 202 gastric adenocarcinomas and 22 normal gastric mucosae was subjected to real-time methylation-specific PCR (Q-MSP). Two regions within the MAL promoter (M1 and M2) were analysed. In addition, 17 frozen gastric carcinomas and two gastric cancer cell lines were analysed both by Q-MSP and real-time RT–PCR. Methylation of M1 and M2 occurred in 71 and 80% of the gastric cancers, respectively, but not in normal gastric mucosa tissue. Hypermethylation of M2, but not M1, correlated with significantly better disease-free survival in a univariate (P=0.03) and multivariate analysis (P=0.03) and with downregulation of expression (P=0.01). These results indicate that MAL has a putative tumour-suppressor gene function in gastric cancer, and detection of promoter hypermethylation may be useful as a prognostic marker.

Colorectal carcinoma: selected issues in pathologic examination and staging and determination of prognostic factors

CONTEXT

Colorectal carcinoma is one of the most common types of cancer in Western countries and is consistently ranked among the top 3 causes of cancer-related deaths, with approximately 150 000 new cases in the United States and 55 000 deaths in 2006. The pathologist's assessment of tumor stage and stage-independent morphologic features, such as vascular/lymphatic invasion, influences treatment strategies for the individual patient, such as the decision to offer adjuvant therapy after surgery. However, although the pathologist influences clinical care in colorectal cancer, certain aspects of staging and evaluation of prognostic factors remain challenging and confusing.

OBJECTIVES

To present the currently used colorectal cancer staging system; to address challenging areas in pathologic staging, including T category considerations and recommendations for the minimum number of lymph nodes sampled; and to discuss assessment of selected stage-independent prognostic factors, such as vascular/ lymphatic invasion.

DATA SOURCES

This review is based on the current staging manual from the American Joint Committee on Cancer, the College of American Pathologists Protocol for Examination of Specimens From Patients With Primary Carcinomas of the Colon and Rectum, and selected articles pertaining to colorectal carcinoma staging and prognostic factors accessible through Ovid Medline (National Library of Medicine, Bethesda, Md).

CONCLUSIONS

Proper assessment of pathologic staging for colorectal cancer and of morphologic prognostic factors requires a thorough understanding of staging guidelines and careful specimen dissection and sampling.

Lumboaortic and iliac lymphadenectomy for lymph node recurrence of colorectal cancer: prognostic value of the MSI phenotype

BACKGROUND

Some patients have isolated lumboaortic and/or iliac lymph node recurrences (ILNR) of colorectal cancer. Current guidelines recommend the use of chemotherapy. The aim of our study was to assess the carcinological results of lymphadenectomy for ILNR and to identify prognostic factors that may be used to select patients for this aggressive surgical approach.

METHODS

Medical notes, pathological findings, and surgical procedure of patients who underwent lymphadenectomy for ILNR of colorectal cancer between 1998 and 2005 were reviewed.

RESULTS

Ten patients (four women) underwent lymphadenectomy for ILNR. Lymphadenectomy was performed after a mean of 37 +/- 16.6 months after colon or rectal resection. Two patients developed a postoperative complication. Mean number of lymph nodes removed was 5.7 +/- 3.3. After a median follow-up of 30.7 months, four patients were alive, including two patients without recurrence at 95 and 96 months after colectomy and two with local and distant recurrences at 114 and 70 months. Among the three patients with microsatellite-unstable (MSI) tumors, two were free of disease at 61 and 81 months, respectively, and one died of recurrent disease 20 months after lymphadenectomy.

CONCLUSION

Lymphadenectomy for ILNR of colorectal cancer is a feasible therapeutic option for selected patients. These preliminary results suggest that resection should be proposed for MSI patients because cure is possible, but to be confirmed, the findings require larger studies.

Association of family history with cancer recurrence and survival among patients with stage III colon cancer

CONTEXT

A family history of colorectal cancer in a first-degree relative increases the risk of developing colorectal cancer. However, the influence of family history on cancer recurrence and survival among patients with established disease remains uncertain.

OBJECTIVE

To examine the association of family history of colorectal cancer with cancer recurrence and survival of patients with colon cancer.

DESIGN, SETTING, AND PARTICIPANTS

Prospective observational study of 1087 patients with stage III colon cancer enrolled in a randomized adjuvant chemotherapy trial (CALGB 89803) between April 1999 and May 2001. Patients provided data on family history at baseline and were followed up until March 2007 for disease recurrence and death (median follow-up, 5.6 years). In a subset of patients, we assessed microsatellite instability (MSI) and expression of the mismatch repair (MMR) proteins MLH1 and MSH2 in tumor specimens.

MAIN OUTCOME MEASURES

Disease-free survival, recurrence-free survival, and overall survival according to the presence or absence of a family history of colorectal cancer.

RESULTS

Among 1087 eligible patients, 195 (17.9%) reported a family history of colorectal cancer in a first-degree relative. Cancer recurrence or death occurred in 57 of 195 patients (29%; 95% confidence interval [CI], 23%-36%) with a family history of colorectal cancer and 343 of 892 patients (38%; 95% CI, 35%-42%) without a family history. Compared with patients without a family history, the adjusted hazard ratios (HRs) among those with 1 or more affected first-degree relatives were 0.72 (95% CI, 0.54-0.96) for disease-free survival, 0.74 (95% CI, 0.55-0.99) for recurrence-free survival, and 0.75 (95% CI, 0.54-1.05) for overall survival. This reduction in risk of cancer recurrence or death associated with a family history became stronger with an increasing number of affected first-degree relatives. Compared with participants without a family history of colorectal cancer, those with 1 affected relative had a multivariate HR of 0.77 (95% CI, 0.57-1.04) for disease-free survival. For participants with 2 or more affected relatives, we observed a greater reduction in risk (multivariate HR for disease-free survival, 0.49; 95% CI, 0.23-1.04; P for trend with increasing number of affected relatives = .01). The improved disease-free survival associated with a family history was independent of tumoral MSI or MMR status.

CONCLUSION

Among patients with stage III colon cancer receiving adjuvant chemotherapy, a family history of colorectal cancer is associated with a significant reduction in cancer recurrence and death.

Microsatellite instability did not predict individual survival in sporadic stage II and III rectal cancer patients

OBJECTIVES

Tumors with high-frequency microsatellite instability (MSI-H) have unique biological behavior and the predictive role of microsatellite instability (MSI) status on survival of colorectal cancer is still debated. The prognostic significance of MSI status in sporadic stage II and III rectal cancer patients needs to be more precisely defined. So we investigated the relationship between MSI status and clinicopathological features and prognosis in these patients.

METHODS

DNAs from fresh-frozen paired samples of tumors and corresponding normal tissue from 128 stage II and III rectal cancer patients were analyzed for MSI by PCR amplification using markers recommended by a National Cancer Institute workshop on MSI. To assess prognostic significance, Cox proportional hazards modeling was used.

RESULTS

Twelve (9.3%) tumors in our study were MSI-H, 28 (21.9%) were low-frequency MSI (MSI-L) and 88 (68.8%) were microsatellite stable (MSS). Most of the MSI-H tumors compared with MSI-L and MSS tumors were found in female patients (p = 0.031), had mucinous histology (p = 0.023), high grade of differentiation (p = 0.002) and high level of preoperative serum carcinoembryonic antigen (p = 0.005). Rectal cancer patients with MSI-H did not show a better clinical outcome than those with MSI-L/MSS, neither in all cases (p = 0.986) nor in stage II and stage III disease analyzed separately (p = 0.705 and p = 0.664, respectively).

CONCLUSIONS

Data provided here demonstrated there was high incidence of MSI-H and MSI was not a prognostic factor in sporadic stage II and III rectal cancers from the Chinese Han population included in this study. Tumor stage is more suitable than MSI status for prediction of individual survival in sporadic stage II and III rectal cancer patients.

p66 Shc Tumor Levels Show a Strong Prognostic Correlation with Disease Outcome in Stage IIA Colon Cancer

PURPOSE

Most stage IIA colon cancer patients receive no adjuvant therapy despite an estimated 15% risk of disease-related death within 5 years of resection. Prognostication of disease outcome would benefit the clinician by categorizing patients with stage IIA disease by risk. The abundance of the signal transduction proteins p66 Shc and tyrosine-phosphorylated (PY)-Shc in tumor cells is a prognostic indicator of disease outcome in breast cancer, suggesting that Shc analysis may provide prognostic information in stage IIA colon cancer.

EXPERIMENTAL DESIGN

Immunohistochemical staining of p66 Shc and PY-Shc was examined in resection specimens from 240 chemotherapy-naïve patients with stage IIA (T(3)N(0)M(0)) colon cancer from two independent (130 and 110 cases, respectively) retrospective cohorts. Staining was scored on a 0 to 5 scale and correlated with relapse-free survival and disease-specific survival in a multivariate analysis to obtain hazard ratios (HR) for both outcomes.

RESULTS

In a pooled analysis of both cohorts, p66 Shc score was a significant prognostic indicator of relapse-free survival (full-range HR, 13.0; P = 0.012) and disease-specific survival (full-range HR, 36.6; P = 0.004) when analyzed as a continuous variable in a multivariate Cox proportional hazards model stratified by study site and adjusted for age, sex, grade, and lymphovascular involvement. PY-Shc in this multivariate Cox model, however, did not achieve statistical significance for either outcome.

CONCLUSIONS

Measuring p66 Shc tumor levels provides a unique and simple tool for stratifying stage IIA colon cancer patients by risk of recurrence and disease-specific death and may assist in determining treatment strategies for these patients.

Prognostic factors and analysis of microsatellite instability in resected pulmonary metastases from colorectal carcinoma

BACKGROUND

In this study, we analyze our experience with pulmonary resection for metastases from colorectal carcinoma. The aims were to search for factors influencing prognosis and to investigate the presence of microsatellite instability in the primary tumors and the corresponding lung metastases.

METHODS

We identified 81 patients who underwent surgical resection between 1991 and 2004. The microsatellite instability was determined by immunohistochemical evaluation of MSH2 and MLH1 in 117 lesions (41 primary tumors and 76 lung metastases).

RESULTS

Overall 3-, 5-, and 10-year survival rates were 50%, 42%, and 30%, respectively. Univariate analysis showed that stage of the primary tumor (p = 0.037), radicalness of the resection (p = 0.019), and stratification into groups according to the International Registry of Lung Metastases classification (p = 0.039) were prognostic factors. Multivariate analysis showed that stage of the primary tumor (p = 0.030) and the radicalness of the resection (p = 0.014) were independent prognostic factors. All tumors displayed preserved expression of MSH2 and MLH1 and were considered microsatellite stable lesions.

CONCLUSIONS

Pulmonary resection of metastases from colorectal carcinoma results in long-term survival in selected patients. Complete resection, stage of the primary tumor and stratification into groups according to the International Registry of Lung Metastases classification were prognostic factors. All the metastases and the corresponding primary tumors were microsatellite stable lesions. This finding seems to demonstrate that pulmonary metastases are infrequent in colorectal carcinomas with microsatellite instability.

Immunohistochemical staining for mismatch repair proteins, and its relevance in the diagnosis of hereditary non-polyposis colorectal cancer

BACKGROUND

Hereditary non-polyposis colorectal cancer (HNPCC) arises mostly from germline mutations of the mismatch repair genes MSH2 and MLH1. The diagnosis of HNPCC is based on a set of clinical criteria that may be too restrictive to identify all affected patients. Immunohistochemical staining (IHC) for the mismatch repair proteins, MutS homologue 2 (MSH2) and MutL homologue 1 (MLH1), reliably identifies the microsatellite instability phenotype. This study evaluated the ability of IHC to detect germline mutations in an unselected group of patients with colorectal cancer (CRC).

METHODS

All patients with CRC operated on between July 2000 and March 2003, and demonstrating a loss of protein, were contacted. Following informed consent, searchs for germline mutation and methylation of the promoter were performed on normal and tumoral DNA.

RESULTS

Thirty patients agreed to participate, four of whom fulfilled the Amsterdam II criteria. Loss of expression of MLH1 was found in 20 patients, and loss of expression of MSH2 in ten patients. Four of the MLH1-deficient patients had a germline MLH1 point mutation (positive predictive value (PPV) 20 (95 per cent confidence interval (c.i.) 2 to 38 per cent) and 11 had promoter methylation. Seven of the MSH2-deficient patients had a germline MSH2 point mutation (PPV 70 (95 per cent c.i. 54 to 96 per cent), and none showed promoter methylation.

CONCLUSION

MLH1-deficient patients who are young or have a positive family history of cancer should be referred for genetic testing and counselling, whereas MSH2-deficient patients should be counselled in the same way as patients with HNPCC.

Loss of MSH2 protein expression is a risk factor in early stage cervical cancer

BACKGROUND

Loss of mismatch repair (MMR) gene expression has been associated with fewer metastases and improved prognosis in various tumour types.

AIMS

To evaluate the predictive and prognostic significance of loss of MMR protein MSH2 in early stage cervical cancer.

METHODS

Specimens from 218 consecutive patients with early stage, surgically treated cervical cancer were analysed. Median age was 42 years (interquartile range 35-53). International Federation of Gynecology and Obstetrics (FIGO) stages were IB1 (57%), IB2 (25%) and IIA (18%). Histology was 70% squamous cell, 6% adenosquamous and 24% adenocarcinoma. Pelvic lymph node metastasis was present in 66 (30%) patients. Median follow-up was 5.2 years (interquartile range 2.5-7.9). Tissue microarrays (TMAs) were constructed containing three cores of paraffin-embedded tumour per case. MSH2 expression was assessed by immunohistochemistry on TMAs and full sections.

RESULTS

In TMAs MSH2 expression could be analysed in 184/218 (84%) tumours. Loss of MSH2 was observed in 58/184 (32%) tumours, with a moderately strong concordance between TMAs and full sections (kappa = 0.47). In tumours with loss of MSH2, pelvic lymph node metastasis and cancer invasion beyond 10 mm were more frequent (48% vs 25%, and 59% vs 37%, respectively). However, loss of MSH2 expression was not related to recurrence or survival.

CONCLUSION

TMAs are powerful tools for high throughput screening of biological markers for prognostic value in cervical cancer. Absence of MSH2 expression is associated with a high-risk profile in early stage cervical cancer, but does not predict lymph node status with sufficient accuracy to be used in the clinic.

Current status of adjuvant therapy for colon cancer

Due to its frequency and persistently high mortality, colorectal cancer represents a major public health problem. The use of adjuvant chemotherapy has improved prognosis in stage III disease, but much work remains to be done in optimizing adjuvant treatment, including refinement of ability to predict disease course and response to chemotherapy. The FOLFOX4 regimen is now considered standard treatment for stage III disease. Combinations of irinotecan and 5-fluorouracil (5-FU) have not proven to be more effective than 5-FU/folinic acid (FA). Oral fluoropyrimidines (eg, capecitabine, UFT + FA) now offer an alternative to intravenous 5-FU. Adjuvant chemotherapy for stage II colorectal cancer is more controversial. Use of adjuvant chemotherapy does not appear to be justified in patients with no particular risk factors (T3N0 with no poor prognosis factor). In contrast, the risk:benefit ratio in patients with one or more poor prognostic factors (T4 tumor, occlusion or perforation, poorly differentiated tumor, vascular invasion, or < 10 lymph nodes examined) appears to favor adjuvant treatment with FOLFOX4. Ongoing adjuvant trials are evaluating bevacizumab and cetuximab combined with 5-FU and oxaliplatin, and are examining the utility of such potential predictive markers as tumor microsatellite instability and loss of heterozygosity. Duration of therapy and prevention of oxaliplatin neurotoxicity are other critical areas for future research.