Molecular subtypes in early colorectal cancer associated with clinical features and patient prognosis

Purpose: After surgical resection, an ample prognosis variability among stages is observed. Multiple prognostic factors are individually studied and some CRC classifiers have been proposed. Not one have been implemented into clinical practice. Methods/patients: We classified 105 patients with resected CRC (stage I-III) into five molecular subtypes using BRAFV600E and RAS (KRAS; NRAS) status, and the expression of DNA mismatch repair (MMR) proteins (MLH1 and MSH2). Clinicopathological features and DFS) of distincts groups were evaluated. Results and conclusions: RAS and BRAFV600E mutations were detected in 43.8 and 11.4% of patients, respectively. 19% of tumours had lack of expression of any MMR proteins reflecting a system deficiency (dMMR). Patients with any RAS mutation had lower DFS that patients with RAS wild type (wt) (40.23 vs 45.26 months; p value = 0.035). Of a total of five molecular subtypes, three were MMR proficient (pMMR): RAS mutated (39%), BRAFV600E mutated (6.7%) and RAS/BRAFV600E wt (35.2%); and two were dMMR: BRAFV600E mutated (4.8%) and BRAFV600E wt (14.3%). Left side tumours were more frequently observed in pMMR/RAS and BRAFV600E wt subtype, and right side tumours in dMMR subtypes. Among the three pMMR subtypes, a benefit survival was observed for patients without any mutation in BRAFv600E or RAS oncogenes (median of DFS = 45.5 vs 40.98 months in RAS mutated group; p = 0.084 and vs 34.13 in BRAFv600E mutated group; p = 0.031). Molecular classification using these biomarkers can be useful to identify groups with differences in prognosis

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Molecular subtypes in early colorectal cancer associated with clinical features and patient prognosis.

PURPOSE: After surgical resection, an ample prognosis variability among stages is observed. Multiple prognostic factors are individually studied and some CRC classifiers have been proposed. Not one have been implemented into clinical practice. METHODS/PATIENTS: We classified 105 patients with resected CRC (stage I-III) into five molecular subtypes using BRAFV600E and RAS (KRAS; NRAS) status, and the expression of DNA mismatch repair (MMR) proteins (MLH1 and MSH2). Clinicopathological features and DFS) of distincts groups were evaluated. RESULTS AND CONCLUSIONS: RAS and BRAFV600E mutations were detected in 43.8 and 11.4% of patients, respectively. 19% of tumours had lack of expression of any MMR proteins reflecting a system deficiency (dMMR). Patients with any RAS mutation had lower DFS that patients with RAS wild type (wt) (40.23 vs 45.26 months; p value = 0.035). Of a total of five molecular subtypes, three were MMR proficient (pMMR): RAS mutated (39%), BRAFV600E mutated (6.7%) and RAS/BRAFV600E wt (35.2%); and two were dMMR: BRAFV600E mutated (4.8%) and BRAFV600E wt (14.3%). Left side tumours were more frequently observed in pMMR/RAS and BRAFV600E wt subtype, and right side tumours in dMMR subtypes. Among the three pMMR subtypes, a benefit survival was observed for patients without any mutation in BRAFv600E or RAS oncogenes (median of DFS = 45.5 vs 40.98 months in RAS mutated group; p = 0.084 and vs 34.13 in BRAFv600E mutated group; p = 0.031). Molecular classification using these biomarkers can be useful to identify groups with differences in prognosis.

The prognostic value of hTERT expression levels in advanced-stage colorectal cancer patients: a comparison between tissue and serum expression

AIM: Telomeres are regions of highly repetitive, non-coding DNA located at the termini of chromosomes whose principal function is to maintain the structural stability of these ends. In 90% of human tumours, telomere length is maintained by the expression and activation of telomerase reverse transcriptase. Various studies have demonstrated an increase in telomerase activity in tumour tissue, which suggests its possible prognostic value. The main objective of our study was to study the prognostic value of the expression level of telomerase catalytic component (hTERT) in patients with colorectal cancer (CRC). METHODS: We analysed the prognostic value of the ratio of telomerase expression in tumour tissue to telomerase expression in the adjacent healthy mucosa and the prognostic value of the expression level of hTERT in the serum of patients diagnosed with CRC. As secondary objectives of the study, we (1) analysed the correlation between telomerase expression in the serum and that in the tumour tissue and (2) analysed the relationship between telomerase expression and different clinical parameters. RESULTS: Peripheral blood and tissue samples taken from 48 patients with CRC were analysed. No significant differences were observed in disease-free survival (DFS) or overall survival time (OST) between the groups of patients categorised based on the ratio of telomerase expression between tumour tissue and healthy tissue. The correlation index (Pearson's coefficient) between telomerase levels in the serum and those in tissue was 0.32. Our study of the relationship between telomerase levels in the serum and different clinical variables, such as tumour size, ganglion affectation, preoperative carcinoembryonic antigen levels and stage, revealed a higher telomerase expression level in patients with stage IV CRC. There was no significant association between telomerase expression in tumour tissue and the clinical parameters analysed. CONCLUSIONS: The results obtained in our study do not allow us to propose that the level of telomerase expression be used as a prognostic factor in colorectal cancer. Thus, we cannot consider telomerase expression in the serum as a surrogate marker of its expression in tumour tissue (AU)