Genetic heterogeneity in saliva from patients with oral squamous carcinomas - Implications in molecular diagnosis and screening

We performed microsatellite analysis at chromosomal regions frequently alte red in head and neck squamous carcinoma on matched saliva and tumor samples from 37 patients who had oral squamous carcinoma. The results were correla ted with the cytologic findings and traditional clinicopathologic factors t o assess the diagnostic and biological potential of these markers. Our data showed that 18 (49%) of the saliva samples and 32 (86%) of the tumors had loss of heterozygosity (LOH) in at least one of the 25 markers studied. in saliva, the combination of markers D3S1234, D9S156, and D17S799 identified 13 (72.2%) of the 18 patients with LOH in saliva (P < 0.001). For tumors, m arkers D3S1234, D8S254, and D9S171 together identified 27 (84.3%) of the 32 tumors with LOH at any of the loci tested (P < 0.001). Eleven (55%) of the 20 saliva samples with cytologic atypia and seven (35%) of the 17 specimen s without atypia had LOH. Significant correlation between LOH in tumor at c ertain markers and smoking and alcohol use was found. Our results indicate that: 1) epithelial cells in saliva from patients with head and neck squamo us tumorigenesis provide suitable material for genetic analysis; 2) combine d application of certain markers improves the detection of genetic alterati on in these patients; 3) clonal heterogeneity between saliva and matching t umor supports genetic instability of the mucosal field in some of these pat ients; and 4) LOH at certain chromosomal loci appears to be associated with smoking and alcohol consumption.