Although several studies have found overexpression of epidermal growth factor receptor (EGFR) proteins EGFR and Her-2 in head and neck cancers, the clinical relevance of the finding varies. We examined the expression and clinical association of these molecules with oral squamous cell carcinoma in an area where betel chewing is prevalent. EGFR and Her-2 proteins were measured in 59 paired (grossly normal and cancer) tissues by an enzyme immunoassy method. The cutoff value for gene overexpression was defined as the level of mean expression in normal tissue plus two s.d. A total of 59% of the patients consumed alcohol, 90% smoked tobacco, and 90% chewed betel quid. Of the patients assayed, 34 (58%) and 24 (41%) had EGFR and Her-2 overexpression, with average 3.5-and 1.5-fold elevations. EGFR overexpression has been shown to be statistically associated with T stage, N stage, overall TMN stage, primary tumour depth, lymph node extra-capsular spread, and poor survival. Her-2 overexpression, however, did not demonstrate a similar association with clinicopathological parameters or therapeutic outcome. On multivariant analysis, EGFR overexpression (P ¼ 0.041) and N stage (P ¼ 0.024) were the only independent factors for overall survival. These results indicate that the molecular targeting therapy to EGFR may be a treatment for oral cavity cancer in the betel quid-chewing prevalent area.

The present study was designed to examine whether different p53 haplotypes of exon 4 -intron 3 -intron 6 affect the frequency of mutations and loss of heterozygosity (LOH) of the p53 gene in male oral squamous cell carcinomas (OSCCs) in Taiwan. We found that individuals without two Pro-W-G alleles had significantly higher frequency of p53 mutations than those with two Pro-W-G alleles (odds ratio (OR) ¼ 1.98; 95% confidence interval (CI), 1.10 -3.56). Out of the 172 p53 gene exon 4 informative male OSCCs, 72 (41.9%) showed LOH. Among these 72 OSCCs with LOH, the frequency of Pro allele loss was 73.6% (53/72). It is notable that alcohol drinking increased the frequency of Arg allele loss (OR ¼ 10.56; 95% CI, 1.23 -234.94) in OSCCs from patients who both smoked cigarettes and chewed areca quid (AQ). The frequency of LOH of p53 was not different between p53-mutated OSCCs and p53-normal OSCCs. Thus, the present study revealed that (a) the Arg allele is associated with p53 mutations, (b) the Pro allele is preferentially lost in OSCCs associated with cigarette smoking and AQ chewing, while the frequency of Arg allele loss is increased with alcohol drinking, and (c) haploinsufficiency of p53 is in itself likely to contribute to tumour progression in Taiwanese OSCCs.

This multicenter study evaluated the mutation spectrum and frequencies of the MLH1 and MSH2 genes and determined the occurrence of large genomic deletions in 93 unrelated Taiwanese families that fulfilled the Amsterdam criteria II by denaturing high-performance liquid chromatography analysis, DNA sequencing for aberrant chromatograms, and multiplex ligation-dependent probe amplification analysis. In total, 38 pathogenic mutations (10 large deletions and 28 point mutations or small deletion/insertions) in the MSH2 or MLH1 gene were identified in 61 of the 93 families (66%). Three of the 10 large deletions and 14 of the 28 point mutations or small insertions/deletions have not been reported elsewhere. Three mutations in the MLH1 gene, the MLH1c.1846_1848delAAG (5 families), deletion exons 11-15 (4 unrelated families), and MLH1c.793C>T (13 unrelated families), accounted for 35% of all cases with pathogenic mutations. Haplotype analysis indicated that mutant c.793C>T alleles were derived from two distinct common founders that might be inherited from a single ancestor of presumably Chinese origin. As a mutation detection strategy for Taiwanese Lynch syndrome patients, we recommend that diagnosis starts with screening for large genomic deletions and continues by screening for common mutations in exons 10 and 16 of the MLH1 gene prior to searching for small mutations in the remaining exons.