GALACTOSYLGLOBOSIDE EXPRESSION IN SEMINOMA - INVERSE CORRELATION WITHMETASTATIC POTENTIAL

Background. Altered glycosylation is a common phenotype expressed in e ssentially all types of human cancer and has been found to be correlat ed closely with the invasive and metastatic properties of a given tumo r. Because there was no prognostic information concerning aberrant gly cosylation of seminoma, the authors studied this topic. Methods. Glyco sphingolipid (GSL) composition of orchiectomy samples of seminoma were analyzed systematically. GSL patterns from seminoma samples of the fo llowing three groups were compared after a 44-month postoperative peri od: Stage I disease with no evidence of metastasis during the 44-month postoperative period, Stage I with metastatic relapse during this per iod, and Stage II with retroperitoneal lymph node metastasis. Unknown GSLs detected were analyzed chemically by H-1-nuclear magnetic resonan ce spectroscopy and mass spectrometry. Results. All nonmetastatic semi nomas (n = 12) contained a GSL band that was identified as galactosylg loboside (Gb(5); Gal beta 1 --> 3GalNAc beta 1 --> 3Gal alpha 1 -->4 G al beta 1 --> 4Glc beta 1 --> 1Cer). All metastatic seminomas (n = 5) lacked this GSL, although the sample sizes were admittedly small. Conc lusion. Only the presence or absence of galactosylgloboside (Gb(5)), b ut of no other GSL or gangliosides, clearly correlated with metastatic potential in patients with seminoma. This observation is useful in th e estimation of prognosis of patients with seminoma, especially those with Stage I disease.