Aberrant methylation of p16, DLEC1, BLU and E-cadherin gene promoters in nasopharyngeal carcinoma biopsies from Tunisian patients.

BACKGROUND

Aberrant methylation of tumor suppressor gene (TSG) promoters has been extensively investigated in nasopharyngeal carcinomas (NPC) from South East Asia but not from North Africa.

PATIENTS AND

METHODS

The methylation status of p16, deleted in lung and esophageal cancer (DLEC1), zinc finger, MYND-type containing 10 (BLU) and E-cadherin gene promoters was investigated in 44 Tunisian NPC biopsies and three NPC xenografts, by methylation-specific PCR (MSP) combined with a quantitative assessment of some of the samples.

RESULTS

The frequencies of aberrant promoter methylation were similar to previous figures reported for Asian series: p16 27/44 (65%), DLEC1 38/44 (86.3%), BLU 15/44 (34.1%) and E-cadherin 35/44 (79.5%). Although in other malignancies, aberrant promoter hypermethylation increases with patient age, it was at the same high frequency in the juvenile and adult forms of Tunisian NPCs. However, there was a strong association between aberrant methylation of E-cadherin promoter and lymph node invasion (p < 0.01). In addition, aberrant methylation of the BLU promoter was significantly correlated with an undifferentiated histological type (p = 0.03).

CONCLUSION

Aberrant methylation of tumor suppressor genes occurs with the same high frequency in NPCs from North Africa as in South East Asia, regardless of patient age.