['Previous studies of oral carcinomas have shown that both loss of heterozygosity (LOH) and hypermethylation at chromosome 9q33 to 9q34.2 are frequent. The present study investigates the frequency of Notch1 gene methylation and LOH at 9q34.3 region.', 'Gene promoter hypermethylation of the Notch1 gene was analysed by methylation-specific PCR and LOH was analysed using microsatellite markers.', 'We found LOH at 9q34.3 in three patients and methylation of the Notch1 gene only in two patients with oral carcinoma.'] Do lOH at chromosome 9q34.3 and the Notch1 gene methylation are less involved in oral squamous cell carcinomas?