Application of Newly Developed Tissue-arrays to Study EMMPRIN (CD147) Expression in Malignant Non-Hodgkin Lymphoma

Matrix-metalloproteinases (MMP) are involved in a broad spectrum of physiological processes. Moreover, they also play a key role in tumour invasion and metastatic spread. The induction of MMPs is mediated via the extracellular matrix-metalloproteinase inducer (EMMPRIN). EMMPRIN is expressed in a variety of epithelial tumours, but expression in non-Hodgkin lymphomas has not been studied yet.

Therefore we studied 201 non-Hodgkin lymphomas (NHL) for EMMPRIN expression by immunohistochemistry using a newly developed tissue microarray (TMA). This new approach to TMA-technology entails the great advantage that areas of interest (for instance with high tumour cell content) are selected by means of serial sections, thus maintaining appropriate samples of each case on the array. The samples were evaluated with regard to the number of positive tumour cells and staining intensity.

All specimens on the arrays contained a sufficient amount of tumour cells. Immunohistochemistry yielded satisfactory results in 196 out of 201 cases. EMMPRIN was expressed in a significantly higher number of tumour cells in high-grade NHL compared with low-grade NHL. Furthermore, the staining intensity was significantly stronger in high-grade NHL.

We report on a new type of TMA that allows effective parallel analysis of a large number of tissue samples. Our data indicate that the expression of EMMPRIN is strongly associated with a more aggressive lymphoma type. However, additional studies are required to elucidate the role of EMMPRIN in the tumour biology of NHL. Possibly, EMMPRIN could be a new target in the therapy of NHL.