Objective: To explore the relationship between hypermethylation of the PTEN gene promoter and laryngeal squamous cell carcinoma (LSCC).
Method: Promoter hypermethylation and mRNA expression were detected by methylation specific PCR and RT-PCR in LSCC and normal laryngeal tissue.
Result: Among the 40 patients with LSCC, hypermethylation of PTEN gene promoter was detected in 16 cases (40.0%). Among the nine normal laryngeal tissues, hypermethylation of PTEN gene promoter was detected in no case. The high and moderate expression rates of PTEN gene mRNA in nine normal laryngeal tissues were 77.8% (7/9) and 22.2% (2/9), respectively; The high, moderate, low and negative expression rates of PTEN mRNA in 15 laryngeal cancers with lymph node metastasis were 26.7% (4/15), 33.3% (5/15), 26.7% (4/15) and 13.3% (2/15), respectively. The PTEN mRNA expression in normal laryngeal tissues was higher than that in the laryngeal cancers with lymph node metastasis (P < 0.05). The high, moderate and low expression rates of PTEN mRNA in 10 highly differentiated laryngeal cancers were 60.0% (6/10), 30.0% (3/10) and 10.0% (1/10), respectively; The high, moderate, low and negative expression rates of PTEN mRNA in 12 low differentiated laryngeal cancers were 16.7% (2/12), 25.0% (3/12), 41.7% (5/12) and 16.7% (2/12), respectively. The differences of PTEN mRNA expression between high and low differentiation laryngeal cancers were statistically significant (P < 0.05). The hypermethylation rate of PTEN gene promoter in the low mRNA expression laryngeal cancers was 70.0% (7/10), the hypermethylation rate of PTEN gene promoter in the high mRNA expression laryngeal cancers was 23.5% (4/17). The hypermethylation rate of PTEN gene promoter in the low mRNA expression laryngeal cancers was higher than that in the high mRNA expression laryngeal cancers (P < 0.05).
Conclusion: Hypermethylation of PTEN gene promoter is associated with loss of its transcription in laryngeal squamous cell carcinoma, the decreasing of PTEN mRNA expression may be related to lymph node metastasis and low differentiation of laryngeal squamous cell carcinoma.