Prognostic Impact of LGR5, Prox1, and Notch1 Biomarkers in Stage II to III Colon Cancer.

The potentiation and activation of Wnt signaling pathways are now assumed to mediate the self-renewal and proliferation of colon cancer stem cells that are responsible for therapeutic resistance, tumor relapse, and metastasis. We aimed to evaluate LGR5, Prox1, and Notch1 immunohistochemical expression in stage II to III colon cancer. Their predictive role of tumor relapse, overall survival, and disease-free survival was statistically analyzed. Our results revealed that high LGR5 expression was identified in 56.7% of the patients, LGR5 expression was significantly associated with left-sided tumors (P<0.001). Moreover, its expression was significantly associated with the unfavorable tumor characteristics including high grade, deep invasion (pT), lymph node metastasis, and advanced tumor stage (P<0.001 for each). High Prox1 expression was observed in 65% of the cases, and its expression was significantly associated with tumor grade, lymph node metastasis, and the advanced tumor stage (P=0.004, 0.009, 0.016, respectively). Positive Notch1 expression was identified in 35% of patients, and it was inversely associated with high grade lymph node metastasis, deep invasion (pT), and advanced tumor stage (P<0.001 for each). During the follow-up period, the tumor relapse was significantly associated with high LGR5, high Prox1, and negative Notch1 expression. Shorter overall survival and disease-free survival were significantly associated with high LGR5, high Prox1, and negative Notch1 expression. High LGR5, high Prox1, and negative Notch1 expression are unfavorable prognostic factors in colon cancer. Prox1 is a crucial regulator of Notch-independent LGR5+ stem cells that is mostly responsible for relapse and therapeutic resistance in stage II to III colon cancer.