OBJECTIVEThe aim of this study was to investigate the expression of microRNA-100 (miR-100) and its relation with prognosis in colorectal cancer (CRC).

METHODSThe expression of miR-100 was analyzed by quantitative real-time PCR (qRT-PCR) in 172 CRC tissue samples. The relation of miR-100 expression patterns with clinical pathological significance in CRC was analyzed. The effects of alterations of miR-100 expression and its consequences on CRC cell proliferation, apoptosis and migration were demonstrated in cells cultured in vitro.

RESULTSThe relative expression of miR-100 in CRC tissues and peritumoral tissues were -6.185 ± 1.921 and -3.698 ± 1.786, respectively, with a significant difference between the two groups (P<0.01). There was a significant difference between the relative expression of miR-100 in CRC with lymph node metastasis (-5.706 ± 1.809) and without lymph node metastasis (-6.775 ± 1.902, P<0.01). The relative expression of miR-100 in tumors of different TNM stages were -7.267 ± 1.888 in stage I, -6.443 ± 1.859 in stage II, -5.923 ± 1.796 in stage III, and -4.639 ± 1.516 in stage IV, with a significant difference among them (P<0.01). Different differentiation grades showed different expression of miR-100, i.e. -7.389 ± 1.828 in well differentiated tumors, -6.095 ± 1.843 in moderately differentiated tumors, and -5.476 ± 2.088 in poorly differentiated tumors (P<0.01). There was no significant correlation between miR-100 expression and overall survival rates of the CRC patients (P=0.179). Overexpression of miR-100 in the CRC cell line HCT-8 inhibited cell proliferation, but promoted cell apoptosis and migration.

CONCLUSIONSThe expression of miR-100 is correlated with lymph node metastasis, TNM stage and differentiation grade, and may be a potential biomarker indicating the development of CRC.