Expression of endostatin in merkel cell carcinoma

The aim of this study was to examine the expression of endostatin in Merkel cell carcinoma (MCC) and to correlate the expression with tumour growth and the development of metastasis.

The study comprised 19 patients treated for MCC at the Helsinki University Hospital, Helsinki, Finland between 1987 and 2003. Endostatin expression was studied by immunohistochemistry. The correlations between the quantitative expression of endostatin and tumour parameters were analysed statistically.

The expression of endostatin was documented in only 40% of the samples. Endostatin correlated negatively with tumour size, and was expressed in 30% of the large and 56% of the small tumours. There was no difference in expression between tumours expanding to metastases and tumours with more indolent behaviour. The simultaneous expression of vascular endothelial growth factor receptor-2 and endostatin was distinguished in small-sized tumours.

This study showed a correlation between endostatin expression and small tumour size in Merkel cell carcinoma. This finding was further confirmed by the finding that tumours positive for VEGFR-2, but not for endostatin, seemed to be larger than tumours that showed simultaneous expression of VEGFR-2 and endostatin.