Nuclear maspin expression: A biomarker for budding assessment in colorectal cancer specimens

To evaluate the maspin expression in colorectal carcinomas (CRC) and its possible role in quantification of the tumor budding.

The tumor budding was prospectively quantified in 49 consecutive cases of patients that underwent surgical resection for CRC. The cases were divided in two groups: group A (n=23) - low budding (<5 tumor buds per high microscopic field) and group B (n=26) - high budding CRCs (≥5 buds). Maspin expression was evaluated in the tumor core and the buds from the hot spot area in 44 of the microsatellite stable adenocarcinomas. Its expression was quantified as negative, cytoplasmic only, nuclear only or mixed expression (cytoplasm and nucleus).

Compared with group A, a higher pT (p <0.0001) and pN stage (p=0.0001) and infiltrating aspect at macroscopic evaluation (p=0.0081) was identified in group B. No correlation between the maspin expression in the tumore core and the budding grade was noted (p=0.14). Compared with the tumor core, the cytoplasm to nuclear translocation of maspin was more frequently observed in cases from group B than A (n=0.0063).

For the colorectal carcinomas, the infiltrative aspect at macroscopic evaluation and nuclear maspin in the buds might be used as indicators of risk for lymph node metastases. Maspin nuclear expression in the buds may be helpful for a proper budding assessment and may serve as a negative prognostic factor.