Background: Recently, the ganglioside Fucosyl-GM1 (FucGM1) has been described as a possible new tumour marker for small-cell lung cancer (SCLC). FucGM1 has been detected in 75% to 90% of SCLC tumours by immunohistochemical analysis and in about 50% of sera from SCLC patients. Neuron-specific enolase (NSE) is a glycolytic enzyme which is expressed in the majority of SCLC tumours and patient sera.
Patients and methods: Sera from 156 patients with SCLC were analyzed for FucGM1 with a scintillation proximity assay (SPA), which is a simple and sensitive analysis. Sera were analyzed before the initiation of chemotherapy, and twenty patients were monitored during and after treatment. The concentration of FucGM1 was compared to the tumour marker NSE and related to clinical data and survival.
Results: Sixty-three per cent of the patients were positive for FucGM1. The concentrations did not correlate with NSE or clinical data including stage of disease, organ site of metastases or ABO blood group status. Nor did the expression of FucGM1 correlate with survival. As a monitor of clinical response, a correlation was found in 8 out of 20 patients. Eighty-four per cent of the patients were positive for NSE; and 97% were positive for either FucGM1 or NSE.
Conclusion: We conclude that FucGM1 does not have a clinical role as a tumour marker for patients with SCLC at diagnosis or during treatment.