Clinical significance of expression of PI3Kp110α, PI3Kp110β, Bcl-2 and CyclinD1 in primary colorectal cancer and lymph node metastases

AIM: To investigate the expression of phosphatidylinositol 3-kinase (PI3K)p110α, PI3Kp110β, B-cell lymphoma-2 (Bcl-2) and CyclinD1 in primary colorectal cancer (CRC) and lymph node metastases, and to analyze their correlations with clinicopathologic characteristics and prognosis of CRC.

METHODS: Immunohistochemistry was used to detect expression of PI3Kp110α, PI3Kp110β, Bcl-2 and CyclinD1 in 30 cases of normal colorectal mucosa, 52 cases of CRC without lymph node metastasis, 50 cases of primary CRC tissues and corresponding lymph node metastases. The correlations between PI3Kp110α, PI3Kp110β, Bcl-2, and CyclinD1 expression as well as their relationship with clinicopathologic characteristics and prognosis of CRC were analyzed.

RESULTS: The expression of PI3Kp110α and Bcl-2 in CRC without lymph node metastasis, primary CRC tissues and corresponding lymph node metastases was significantly higher than that in normal colorectal mucosa (P < 0.05). PI3Kp110β and CyclinD1 expression was also significantly increased in CRC without lymph node metastasis, primary CRC tissues, and corresponding lymph node metastases compared with the normal colorectal mucosa. What's more, PI3Kp110β and CyclinD1 expression was significantly increased in CRC with lymph node metastases compared with CRC without lymph node metastases (P < 0.05). Spearman analysis showed that PI3Kp110α expression was positively associated with Bcl-2 expression in the four groups (P < 0.05), PI3Kp110α expression was positively associated with CyclinD1 expression in normal colorectal mucosa, CRC without lymph node metastasis, and CRC with lymph node metastasis (P < 0.05), and PI3Kp110β expression was positively correlated with Bcl-2 and CyclinD1 expression in the four groups (P < 0.05). PI3Kp110α, PI3Kp110β and CyclinD1 expression was related to cancer cell differentiation and lymph node metastasis, and Bcl-2 expression was associated with cancer cell differentiation. Kaplan-Meier analysis showed that PI3Kp110α, PI3Kp110β, Bcl-2 and CyclinD1 were prognostic factors for CRC, and Cox proportional hazards regression analysis showed that PI3Kp110α and PI3Kp110β were independent prognostic factors for CRC.

CONCLUSION: PI3Kp110α, PI3Kp110β, Bcl-2, and CyclinD1 expression is increased in primary CRC tissues and lymph node metastases compared with normal mucosa, suggesting that they may play important roles in the development and progression of CRC. PI3Kp110α and PI3Kp110β promote cancer cell growth via Bcl-2 and CyclinD1 in CRC with lymph node metastases. PI3Kp110α, PI3Kp110β, Bcl-2 and CyclinD1 are associated with tumor cell differentiation and CRC metastasis. PI3Kp110α and PI3Kp110β are independent prognostic factors for CRC.