[Clinicopathological significance of expressions of DNA dependent protein kinase catalytic subunit and P16 in colorectal carcinoma].

Objective: To investigate the expression of DNA dependent protein kinase catalytic subunit (DNA-PKcs) and P16 (multiple tumor suppressor 1) genes in colorectal carcinoma and clinical significance thereof.
Methods: 359 specimens of colorectal carcinoma obtained during operation and 35 specimens of normal mucosa beside the carcinoma underwent immunohistochemical examination and Western blotting to detect the expression of DNA-PKcs and P16.
Results: The positive expression rates of DNA-PKcs and P16 of the colorectal carcinoma specimens were 63.5% (228/359) and 53.2% (191/359) respectively, both significantly higher than those of the para-cancer normal tissues (both P < 0.05). DNA-PKcs and P16 expression were both related to the clinical stage, lymphatic invasion, and distant metastasis (all P < 0.05). The 5-year survival rates of the patients positive in DNA-PKcs and P16 expression were significantly lower than those of the patients negative in DNA-PKcs and P16 expression (both P < 0.05). The DNA-PKcs positive rate of the P16-positive patients was 78.6%, significantly higher than that of the P16-negative patients (55.3%, r = 0.149, P = 0.036).
Conclusion: DNA-PKcs and P16 play a significant role in the carcinogenesis and evolution of colorectal carcinoma and may be used as one of the useful indicators for clinical assessment of tumor biological behavior and prognosis of colorectal carcinoma.