When ALDH1 immunostaining was classified into negative (ALDH1+ tumour cells <5%), 1+ (⩾5%, <10%,), 2+ (⩾10%, <50%) and 3+ (>50%) groups, there were 80 (87.0%), 3 (3.3%), 8 (8.7%) and 1 (1.1%) cases assigned to the negative, 1+, 2+ and 3+ groups, respectively. This evidence concerns the gene ALDH1A1 and neoplasm.