There was a significant difference in MGMT expression between smokers and non-smokers (in whom the protein was more frequently reduced)6 and between ADC and LCC, with none of the LCCs showing loss of expression, whereas in our study we did not demonstrate any association with tumour type and found loss of expression in a considerable number of LCCs (68.4%). The gene discussed is MGMT; the disease is leukoencephalopathy with calcifications and cysts.