Implications of cleaved caspase 3 and AIF expression in colorectal cancer based on patient age.

A high incidence of colorectal cancer (CRC) has been established in the elderly population. Apoptosis is a key event in maintaining colon homeostasis, both in aging as well as in cancer prevention. Here, we report that colon morphology is affected during the aging process: crypt loss (P=0.045) and increasing distances between crypts (P=0.0001678) were observed, associated with a tendency for mucosa reduction (P=0.083). In addition, our results show that apoptosis plays a determining role on the effect of aging during CRC. Increased expression of cleaved caspase 3 (the key factor implicated in the caspase-dependent pathway; P=0.026 for non-tumor tissues, P=0.0013 for tumor tissues) and AIF (implicated in the caspase-independent pathway; P=0.037) in tissue from elderly patients has been observed. Furthermore, elderly patients respond better to chemotherapy than younger ones (P=9.27 x 10(-5)). These results suggest that patient age should be taken into account to adapt treatment of CRC.