Cáncer de colon en Colombia, fenotipo molecular: tamizaje para síndromes con agregación familiar

Objective: To characterize the main clinicopathological features and the molecular phenotypes of Colorectal Carcinoma (CRC), in 1,278 patients from the Colombian Andean region.Methods: 1278 patients with CRC. Analyses of the MMR (Mismatch Repair) genes hMLH1, immunohistochemical methods (IHC) were used. To evaluate microsatellite instability (MSI), DNA from tumoral-normal tissue by PCR.Results: The average age of Colombian CRC patients is 57.4 years. The disease is more common in females (53.2%). The frequency of patients younger than 50 years (26.5%) is higher than expected; the CRC in these cases was associated with histological types: aggressive, mucinous carcinoma and singlet ring carcinoma (P= <0.000), which in turn were associated with microsatellite instability (MSI-H). The most frequent location was in the rectum (31.3%), p=0.002 and the diagnosis occurred in advanced stages of the disease T3-T4 (75.1%) p=0.022. The most common histological type was adenocarcinoma.The sensitivity of the immunohistochemical analysis of MLH1 for the detection of MSI+ was 71% (Cl: 49-87). In 575 cases, the IHC-MLH1 analysis showed loss of expression in 7% of patients. MSI analysis was performed in 451 cases of CRC, with 25% show in high microsatellite instability (MSI-H).Conclusions: The determination of microsatelital instability and immunohistochemistry for MMRs allow to identify patients at risk of being carriers of mutations related to Lynch syndrome in Colombian patients.