The family of apoptosis-stimulating proteins of p53 is dysregulated in colorectal cancer patients

The apoptosis-stimulating protein of p53 (ASPP) family is a newly identified family protein including ASPP1, ASPP2 and inhibitor of ASPP (iASPP), by which the tumor protein 53 (TP53)-mediated apoptotic process is selectively regulated. Downregulation of ASPP1/ASPP2 and upregulation of iASPP were revealed to be associated with a poor prognosis and metastasis in several types of cancer. However, to the best of our knowledge, the expression of ASPP in colorectal cancer (CRC) has not previously been investigated. The present study analyzed ASPP expression in human CRC tissues with multiple clinical and pathological profiles. A total of 41 patients diagnosed with CRC were enrolled in the present study. The expression of ASPP was detected by immunohistochemistry, immunofluorescence and reverse transcription-quantitative polymerase chain reaction. In addition, the variation in ASPP expression was examined in a number of pathological groups. The associations among ASPP expression, and the expression of TP53, plasma carcinoembryonic antigen (CEA) levels and α-fetoprotein (AFP) levels were also investigated. ASPP1 and ASPP2 expression was significantly reduced, while iASPP expression was elevated in CRC samples compared with expression in adjacent non-cancerous tissues. Downregulation of ASPP1 was detected in the TP53-positive group compared with the TP53-negative group. The increase in iASPP expression was correlated with the grade of malignancy, but not with regional lymph node status or metastases. The expression of ASPP2 was negatively correlated with plasma CEA levels. The results of the present study, not only enrich CRC epidemic and pathological data, but also provide valuable indices for CRC clinical treatment and prognosis.