Objective: To elucidate the role of DLC1 gene in nasopharyngeal carcinoma (NPC).
Methods: The expression of DLC1 was studied by means of RT-PCR combined with sequencing in 32 cases non-keratinizing carcinoma, 16 cases of histologically normal nasopharyngeal epithelia, and 4 NPC cell lines (CNE1, CNE2 and HNE1, HNE2).
Results: The expression of functional transcript of DLC1 was undetected in all NPC cell lines, and it was significantly reduced or undetected in NPC biopsies in comparison with normal nasopharyngeal mucosae (P < 0.001). The expression of DLC1 was significantly reduced in T3, T4 stages of NPC biopsies, compared with that in T1, T2 stages (P = 0.01). However, there was no relationship between the expression of DLC1 and other clinical features in NPC patients, such as age, sex, lymph node metastasis, distant metastasis, TNM clinical stages and the serum titer of EBV (VCA/IgA) antibody (P > 0.05). An aberrant transcript of DLC1, which lacked exon 8, was found in 7 cases of NPC and only in 1 case of normal nasopharyngeal mucosae.
Conclusion: DLC1 gene may play a critical role in the tumorgenesis of NPC. The down-expression of DLC1 may be associated with the local invasion of NPC. The aberrant isoform may be related with the dysfunction of DLC1 gene.