Maspin, E-selectin, and P-selectin expressions in papillary thyroid carcinomas and their correlation with prognostic parameters

Maspin is a serine protease inhibitor belonging to the serpin family, and is known as a tumor-suppressor protein. Maspin also exhibits an inhibitor effect on angiogenesis. Cell adhesion molecules such as E- and P-selectin are known to play an important role in the metastasis mechanism. We evaluated the expression of maspin, E- and P-selectin in 74 papillary thyroid carcinomas, 19 of which had lymph node metastases, and statistically analyzed the relationship between these three proteins and their relation with prognostic factors. Positive correlations were found for maspin positivity and lymph node metastases; thyroid capsule invasion and perithyroidal soft tissue invasion; E-selectin positivity and lymph node metastases, lymphovascular invasion and perithyroidal soft tissue invasion; and P-selectin positivity and lymph node metastases and lymphovascular invasion (p < 0.05). Statistically significant correlations were also found between maspin, E- and P-selectin expressions with each other and with tumor stage (p < 0.05). Inactive cytoplasmic maspin cannot act as a tumor suppressor. Expression of E- and P-selectins in tumor cells facilitates the occurrence of metastases, lymphovascular invasion, and perithyroidal soft tissue invasion. Further studies, in particular molecular investigations, are needed to reveal the detailed interactions between maspin, E-selectin, and P-selectin expression.