Practical value of the new system for Maspin assessment, in colorectal cancer

Maspin is a serine protease which belongs to the serpin family and seems to play an important role in inhibiting angiogenesis and tumor proliferation. The significance of its expression in colorectal cancer (CRC) has not been elucidated so far. In our study, we tried to identify, based on Maspin expression, four groups of CRC, with possible prognostic impact. In 121 CRC, we analyzed the Maspin expression in correlation with the clinico-pathological features, microsatellite status and other markers such as p53, bax, bcl-2, VEGF (Vascular Endothelial Growth Factor) and CD31. Based on the percentage and intensity of Maspin expression in the tumor cells, the cases were grouped in four classes: negative, with cytoplasmic predominance, nuclear predominated, and cases with mixed (cytoplasmic-nuclear) expression. 9% of the cases were negative, 44% presented cytoplasmic predominance, the nuclear predominance was revealed in 24% of the cases, and the other 23% of CRC having a mixed Maspin positivity. The cytoplasmic predominance was correlated with a better prognosis, p53 negativity, bax positivity, and lack of tumor budding. Forty percent of microsatellite instable (MSI) cases presented mixed expression, this pattern being also related to a lower angiogenesis. Nuclear predominance was associated with p53 positivity, the lowest survival rate and intense VEGF expression. In conclusion, CRC with cytoplasmic predominance and mixed Maspin expression seems to present better prognosis whereas nuclear predominance is connected with high aggressivity.