Specific c-K-ras Gene Mutations as a Tumor-Response Marker in Locally Advanced Rectal Cancer Treated With Preoperative Chemoradiotherapy

Abstract

The presence of specific c-K-ras mutations is an indicator of tumor response in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy and surgery. Therefore, responding patients may be more amenable to less radical surgical procedures based on c-K-ras mutations.

Biomarkers and Molecular Imaging as Predictors of Response to Neoadjuvant Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer

“…In contrast, Luna-Perez et al observed that wt KRAS tumors were more likely to be responsive than mutated tumors. 24 Although these results should be interpreted with caution because of the many biases, other more recent studies came to similar conclusions, and confirmed an association between KRAS mutations and resistance to NCRT. 20,25 In particular, Duldulao et al performed KRAS and p53 genotyping in 148 patients, and showed that tumors with any KRAS mutation were less likely to have a pCR than those with wt KRAS (P ¼ .006).…”

Neoadjuvant Therapy for Rectal Cancer: Improved Tumor Response, Local Recurrence, and Overall Survival in Nonanemic Patients

“…Unfortunately such a marker remains elusive, although some correlation has been shown with p21 and p53 expression in small, retrospective studies that have used different measures to quantify response. 6,7 For many cancers, it has been shown that the presence of anemia influences the response of the tumor to radiotherapy. This is thought to be because of the intratumoral tissue hypoxia, which is known to be associated with the disordered growth of cancers.…”

The Prognostic Significance of the Expression Change of EGFR during Neoadjuvant Chemoradiotherapy in Patients with Rectal Carcinoma

“…K-RAS mutation status was observed in 6 patients, and the other 30 patients had wild-type K-RAS gene [42]. On the other hand, some studies have shown that no prognostic influence of mutation status of K-RAS gene on patients was observed [33,43]. An interesting fact is the lower incidence of K-RAS mutation status in rectal carcinoma (12-30%) compared to colon carcinoma [43,44].…”

“…On the other hand, some studies have shown that no prognostic influence of mutation status of K-RAS gene on patients was observed [33,43]. An interesting fact is the lower incidence of K-RAS mutation status in rectal carcinoma (12-30%) compared to colon carcinoma [43,44]. The results of studies evaluating the influence of anti-EGFR antibodies with the combination of neoadjuvant chemoradiotherapy for rectal cancer are not satisfactory [27][28][29][30][31][32][33][34][35][36][37].…”