Tumor regression grades, K-RAS mutational profile and c-MET in colorectal liver metastases

The potential therapeutic and prognostic impacts of the c-MET/HGF signaling pathway in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and a common cause of cancer-related mortality globally. In spite of the improvements in the early diagnosis of CRC, approximately one-third of patients develop metastasis and then have a very poor survival rate. The mesenchymal-epithelial transition factor (c-MET) is a tyrosine kinase cell surface receptor activated by hepatocyte growth factor (HGF). Activation of c-MET/HGF signaling pathway regulates a variety of biological processes including cell motility, cell proliferation, angiogenesis, the epithelial-to-mesenchymal transition, and the development and progression of cancer cells. Recent studies have suggested that the c-MET/HGF signaling pathway is involved in the carcinogenesis of CRC. In this review, we summarize the main findings of recent studies investigating the role of c-MET/HGF signaling pathway in CRC and the potential of the c-MET/HGF signaling pathways in the diagnosis and treatment of CRC. © 2019 IUBMB Life, 2019.

Clinical significance and prognostic relevance of KRAS, BRAF, PI3K and TP53 genetic mutation analysis for resectable and unresectable colorectal liver metastases: A systematic review of the current evidence

BACKGROUND

Hepatic resection is considered the optimal potentially curative treatment for colorectal liver metastases (CRLM). Following resection, up to two-thirds of patients will develop recurrence within 5-years. Genetic mutation analysis of CRLM, especially KRAS status, has been proposed as a means to guide treatment, as well as identifying patients who can derive the most survival benefit from hepatic resection.

METHODS

A systematic review of the literature was conducted the PubMed, Embase and Cochrane library through February 8th, 2018. The following algorithm was applied: "(colorectal OR rectal OR colon OR colonic) AND (liver OR hepatic) AND (metastasis OR metastases) AND (gene OR mutation OR KRAS OR BRAF OR SMAD4 OR RAS OR TP53 OR P53 OR APC OR PI3K OR MSI OR EGFR OR MACC1 OR microsatellite)."

RESULTS

From the 2404 records retrieved, 78 studies were finally deemed eligible; 47 studies reported mutational data on patients with resectable CRLM, whereas 31 studies reported on patients with unresectable CRLM. Mutational analyses were mostly performed on the CRLM specimen rather than the primary CRC. The vast majority of studies reported on the KRAS mutational status (88.5%, n = 69/78). Prevalence of KRAS mutations ranged from 25% to 52%. Most studies reported that RAS mutation was a negative prognostic factor for overall (OS) (n = 24) and recurrence-free (RFS) (n = 9) survival; a few reports noted no effect of RAS mutational status on OS (n = 4) or RFS (n = 6). Twelve studies reported on BRAF mutations with a prevalence of BRAF mutation ranging from 0 to 9.1% in resected CRLM specimens. BRAF mutation was strongly associated with a worse prognosis. TP53 and PIK3CA gene mutations did not affect long-term outcomes.

CONCLUSIONS

The biological status of each tumor provides the basis for individualized cancer therapeutics. Data on the mutational status on CRLM should be a part of multidisciplinary discussions to help inform the therapeutic approach, type of chemotherapy, as well as timing and approach of surgical resection.

Upregulation of c-mesenchymal epithelial transition expression and RAS mutations are associated with late lung metastasis and poor prognosis in colorectal carcinoma

The present study aimed to investigate whether c-mesenchymal epithelial transition factor (C-MET) overexpression combined with RAS (including KRAS, NRAS and HRAS) or BRAF mutations were associated with late distant metastases and the prognosis of patients with colorectal cancer (CRC). A total of 374 patients with stage III CRC were classified into 4 groups based on RAS/BRAF and C-MET status for comprehensive analysis. Mutations in RAS/BRAF were determined using Sanger sequencing and C-MET expression was examined using immunohistochemistry. The associations between RAS/BRAF mutations in combination with C-MET overexpression and clinicopathological variables including survival were evaluated. In addition, their predictive value for late distant metastases were statistically analyzed via logistic regression and receiver operating characteristic analysis. Among 374 patients, mutations in KRAS, NRAS, HRAS, BRAF and C-MET overexpression were observed in 43.9, 2.4, 0.3, 5.9 and 71.9% of cases, respectively. Considering RAS/BRAF mutations and C-MET overexpression, vascular invasion (P=0.001), high carcino-embryonic antigen level (P=0.031) and late distant metastases (P<0.001) were more likely to occur in patients of group 4. Furthermore, survival analyses revealed RAS/BRAF mutations may have a more powerful impact on survival than C-MET overexpression, although they were both predictive factors for adverse prognosis. Further logistic regression suggested that RAS/BRAF mutations and C-MET overexpression may predict late distant metastases. In conclusion, RAS/BRAF mutations and C-MET overexpression may serve as predictive indicators for metastatic behavior and poor prognosis of CRC.