KRAS status and clinical outcome in metastatic colorectal cancer patients treated with first-line FOLFOX chemotherapy

Molecular characterization of colorectal cancer related peritoneal metastatic disease

A significant proportion of colorectal cancer (CRC) patients develop peritoneal metastases (PM) in the course of their disease. PMs are associated with a poor quality of life, significant morbidity and dismal disease outcome. To improve care for this patient group, a better understanding of the molecular characteristics of CRC-PM is required. Here we present a comprehensive molecular characterization of a cohort of 52 patients. This reveals that CRC-PM represent a distinct CRC molecular subtype, CMS4, but can be further divided in three separate categories, each presenting with unique features. We uncover that the CMS4-associated structural protein Moesin plays a key role in peritoneal dissemination. Finally, we define specific evolutionary features of CRC-PM which indicate that polyclonal metastatic seeding underlies these lesions. Together our results suggest that CRC-PM should be perceived as a distinct disease entity.

Colorectal cancer can lead to the development of peritoneal metastases, which are associated with worse disease outcome. Here, the authors characterize peritoneal metastases from 52 patients using RNA-seq and mutational sequencing and show a distinct molecular subtype.

A mouse model for peritoneal metastases of colorectal origin recapitulates patient heterogeneity

The peritoneum is a common site of dissemination in patients with colorectal cancer. In order to identify high-risk patients and improve therapeutic strategies, a better understanding of the peritoneal dissemination process and the reasons behind the high heterogeneity that is observed between patients is required. We aimed to create a murine model to further elucidate the process of peritoneal dissemination and to provide an experimental platform for further studies. We developed an in vivo model to assess patterns of peritoneal dissemination of 15 colorectal cancer cell lines. Immune deficient mice were intraperitoneally injected with 10,000 human colorectal cancer cells. Ten weeks after injection, or earlier in case of severe discomfort, the mice were sacrificed followed by dissection including assessment of the outgrowth and localization of peritoneal metastases. Furthermore, using a color-based clonal tracing method, the clonal dynamics of peritoneal nodules were observed. The different cell lines showed great variation in the extent of peritoneal outgrowth, ranging from no outgrowth to localized or widespread outgrowth of cells. An association between KRAS pathway activation and the formation of peritoneal metastases was identified. Also, cell line specific tumor location preferences were observed, with similar patterns of outgrowth in anatomically related areas. Furthermore, different patterns regarding clonal dynamics were found, varying from monoclonal or polyclonal outgrowth to extensively dispersed polyclonal lesions. The established murine model recapitulates heterogeneity as observed in human peritoneal metastases, which makes it a suitable platform for future (intervention) studies.

Review on comparative efficacy of bevacizumab, panitumumab and cetuximab antibody therapy with combination of FOLFOX-4 in KRAS-mutated colorectal cancer patients

Colorectal cancer, fourth leading form of cancer worldwide and is increasing in alarming rate in the developing countries. Treating colorectal cancer has become a big challenge worldwide and several antibody therapies such as bevacizumab, panitumumab and cetuximab are being used with limited success. Moreover, mutation in KRAS gene which is linked with the colorectal cancer initiation and progression further interferes with the antibody therapies. Considering median progression free survival and overall survival in account, this review focuses to identify the most efficient antibody therapy in combination with chemotherapy (FOLFOX-4) in KRAS mutated colorectal cancer patients. The bevacizumab plus FOLFOX-4 therapy shows about 9.3 months and 8.7 months of progression free survival for KRAS wild and mutant type, respectively. The overall survival is about 34.8 months for wild type whereas for the mutant it is inconclusive for the same therapy. In comparison, panitumumab results in better progression-free survival which is about (9.6 months) and overall survival is about (23.9 months) for the wild type KRAS and the overall survival is about 15.5 months for the mutant KRAS. Cetuximab plus FOLFOX-4 therapy shows about 7.7 months and 5.5 months of progression-free survival for wild type KRAS and mutant type, respectively. Thus, panitumumab shows significant improvement in overall survival rate for wild type KRAS, validating as a cost effective therapeutic for colorectal cancer therapy. This review depicts that panitumumab along with FOLFOX-4 has a higher response in colorectal cancer patients than the either of the two monoclonal antibodies plus FOLFOX-4.

The Presence of Mutations in the K-RAS Gene Does Not Affect Survival after Resection of Pulmonary Metastases from Colorectal Cancer

Introduction. Our objective was to identify mutations in the K-RAS gene in cases of pulmonary metastases from colorectal cancer (CRC) and determine whether their presence was a prognostic factor for survival. Methods. We included all patients with pulmonary metastases from CRC operated on between 1998 and 2010. K-RAS mutations were investigated by direct sequencing of DNA. Differences in survival were explored with the Kaplan-Meier method log-rank tests and multivariate Cox regression analysis. Results. 110 surgical interventions were performed on 90 patients. Factors significantly associated with survival were disease-free interval (P = 0.002), age (P = 0.007), number of metastases (P = 0.001), lymph node involvement (P = 0.007), size of the metastases (P = 0.013), and previous liver metastasis (P = 0.003). Searching in 79 patients, K-RAS mutations were found in 30 cases. We did not find statistically significant differences in survival (P = 0.913) comparing native and mutated K-RAS. We found a higher rate of lung recurrence (P = 0.040) and shorter time to recurrence (P = 0.015) in patients with K-RAS mutations. Gly12Asp mutation was associated with higher recurrence (P = 0.022) and lower survival (P = 0.389). Conclusions. The presence of K-RAS mutations in pulmonary metastases does not affect overall survival but is associated with higher rates of pulmonary recurrence.

KRAS mutations and subtyping in colorectal cancer in Jordanian patients

Colorectal cancer (CRC) is one of the most common malignancies in the Western world and Jordan. v-Ki-ras2 Kirsten rat sarcoma (KRAS) mutations represent an early event in the development and progression of CRC. Previous studies have demonstrated that KRAS mutations serve as a predictor of response to EGFR-targeted therapies for patients with metastatic CRC. The aim of this study was to determine the portion of CRC patients with wildtype KRAS status and molecular subtypes of KRAS mutations in Jordan as compared with other countries. DNA was isolated from 100 consecutive colorectal carcinoma specimens from patients who underwent surgical resection or colonoscopic biopsies of colorectal tumors and had developed metastatic disease. KRAS mutations were detected by hybridization-based strip assay as well as RT-PCR-based assay and confirmed by standard Sanger sequencing of codon 12 and 13 of exon 1 of the KRAS gene. Among 100 tested patients, 56% had a wt-KRAS genotype and 44% had a mutated KRAS genotype. The pGly12Asp was the most commonly detected mutation (54.5%). KRAS mutations were independently associated with patient age, gender and tumoral variables. The ratio of mutated versus wt-KRAS patients in this study is similar to those reported in Western countries but contrasts to neighboring Middle Eastern countries. Colorectal carcinoma cases from Jordan had higher KRAS mutation frequencies compared with other Middle Eastern countries which is likely to reflect different molecular pathogenesis and environmental exposures.

KRAS mutations and subtyping in colorectal cancer in Jordanian patients

Colorectal cancer (CRC) is one of the most common malignancies in the Western world and Jordan. v-Ki-ras2 Kirsten rat sarcoma (KRAS) mutations represent an early event in the development and progression of CRC. Previous studies have demonstrated that KRAS mutations serve as a predictor of response to EGFR-targeted therapies for patients with metastatic CRC. The aim of this study was to determine the portion of CRC patients with wildtype KRAS status and molecular subtypes of KRAS mutations in Jordan as compared with other countries. DNA was isolated from 100 consecutive colorectal carcinoma specimens from patients who underwent surgical resection or colonoscopic biopsies of colorectal tumors and had developed metastatic disease. KRAS mutations were detected by hybridization-based strip assay as well as RT-PCR-based assay and confirmed by standard Sanger sequencing of codon 12 and 13 of exon 1 of the KRAS gene. Among 100 tested patients, 56% had a wt-KRAS genotype and 44% had a mutated KRAS genotype. The pGly12Asp was the most commonly detected mutation (54.5%). KRAS mutations were independently associated with patient age, gender and tumoral variables. The ratio of mutated versus wt-KRAS patients in this study is similar to those reported in Western countries but contrasts to neighboring Middle Eastern countries. Colorectal carcinoma cases from Jordan had higher KRAS mutation frequencies compared with other Middle Eastern countries which is likely to reflect different molecular pathogenesis and environmental exposures.