Background & objective: Upward (local growth and invasion of the base of skull), downward (distant metastasis) and mixed progressing types of nasopharygeal carcinoma (NPC) have been observed when the disease progress to middle-late stage. The upward and downward progressing types are evidently different in clinical symptom, therapy strategy and prognosis. Identification of the molecular differences between them is very important for molecular classification, prognostic prediction and research on neoplasia and development of NPC. This study was to discover the genes differentially expressed in upward and downward progressing types of NPC.
Methods: An oligo gene chip containing 21 300 genes was used to detect the genes differentially expressed between upward and downward progressing types of NPC. One of the differentially expressed genes detected was analyzed by reverse transcription-polymerase chain reaction (RT-PCR).
Results: Seventeen genes were differentially expressed between upward and downward progressing types of NPC. The expression of SELB, Clorf29, GLE1L and FLJ20989 genes were up-regulated and the expression of 1D12A, ASPN, DCN, PRO2219, LRDD, DIO2, ULBP2, PRO3073, IGVH3, IGVH4, IGLJ3, PRO0943 and AK057247 genes were down-regulated in the upward progressing type as compared with those in the downward progressing type. The difference of gene expression was ranged from 2.30 to 4.23 folds. The high expression rate of DIO2 gene was significantly higher in downward progressing type than in upward progressing type (90.0% vs. 33.3%, P = 0.020).
Conclusions: The gene expression patterns are significantly different between upward and downward progressing types of NPC. The expression of DIO2 gene is higher in the downward progressing type than in upward progressing type, which may be closely related to the metastasis potential of NPC.