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Using polymerase chain reaction (PCR)-SSCP (single-strand conformation polymorphism) and PCR-DNA sequencing analysis, we screened 61 cases of laryngeal squamous cell carcinoma for mutations in exons 5–8 of the p53 gene. Mutations were found in 31.3% (19 of 61) of the laryngeal cancers. Seventeen of 19 (84.2%) cases showing p53 gene mutations were stage III and IV. which suggests that p53 gene mutation is a rather late event in tumor development and is involved in the progression of laryngeal squamous cell carcinoma. A high frequency of G:C to T:A transversion (50%, seven of 14), especially G to T (35.7%, five of 14), was noted in laryngeal carcinoma samples in our study. This finding may point toward an environmental carcinogen (such as tobacco smoke) as an important agent in the genesis of laryngeal squamous cell carcinoma. Most of the p53 gene mutations (18 of 19) found in our studies could change the protein and thus may cause an inactivation of the p53 tumor suppressor gene, strongly suggesting that p53 gene mutation plays a crucial role in the progression of laryngeal carcinoma.