CD147 expression in pituitary adenomas and its significance for clinical outcome

CD147, a transmembrane glycoprotein member of the immunoglobulin superfamily of receptors, is involved in invasion and angiogenesis of some types of tumors; but its roles and clinicopathologic significance in pituitary adenomas are not clear. Using immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction, we measured the expression of CD147, matrix metalloproteinase-2, and Ki-67 in 74 pituitary adenomas and evaluated the associations of CD147 with matrix metalloproteinase-2, Ki-67 labeling index, clinicopathologic characteristics, and prognosis. The CD147 protein was expressed in 35 (87.5%) of 40 invasive and in 16 (47.1%) of 34 noninvasive pituitary adenomas; and matrix metalloproteinase-2, in 32 (80.0%) and in 14 (41.2%) of 34, respectively. The Ki-67 labeling index was 3.93% +/- 2.48% for invasive samples and 1.32% +/- 1.04% for noninvasive ones. In addition, the expression of CD147 was positively correlated with matrix metalloproteinase-2, Ki-67 labeling index, or both in invasive pituitary adenomas (P< .01 and P< .01, respectively). All of the 4 recurrent adenomas were concurrently positive for CD147 and matrix metalloproteinase-2, and the Ki-67 labeling indexes of all were greater than 3%. Thus, CD147 may play a pivotal role in the development and progression of invasive pituitary adenomas and also be a useful prognostic biomarker.