Expression of the GM1-species, [NeuN]-GM1, in a case of human glioma

Altered glycosylation is a common feature in tumors of various kind and par ticular interest has been focused on the expression of tumor-associated gan gliosides. We have previously identified some human glioma-associated gangl iosides and in this study yet another, not previously described, gangliosid e has been isolated. The ganglioside was prepared from human glioma tissue taken at autopsy. The new ganglioside bound cholera-toxin B-subunit and its structure was confirmed by fast atom bombardment-mass spectrometry to be N euN-GM1 (II(3)NeuNH(2)-GgOse(4)Cer). In the dissected tumor specimen, the c oncentration of NeuN-GM1 was 0.1 mu mol/g wet weight and accounted for appr oximately 20% of the monosialoganglioside fraction. Normal human brain tiss ue specimens (n = 10) did not contain detectable (>0.5 nmol/g wet weight of tissue) amounts of NeuN-GM1, indicating that this ganglioside might be ass ociated with human glioma. However, none of the 17 other tumour specimens r eveal any detectable amounts of this ganglioside. In conclusion, NeuN GM1 i s a glioma-associated ganglioside but its exceptional expression limits its relevance as a molecule involved in general tumor biology.