Identification of differentially expressed genes in esophageal cancer through SSH in combination with high throughput reverse Northern screening

To understand the molecular mechanisms of carcinogenesis of esophagus and t o isolate genes with different expression levels in esophageal cancer, supp ression subtractive hybridization (SSH) was combined with PCR-based cDNA sy nthesis and reverse Northern on the cancer tissues and matched almost norma l mucosa using 5 microgram of total RNA as starting marterial. Eight genes were found expressed differentially in esophageal cancer, in which 5 were k nown genes and 3 were novel ones; and 6 were down-regulated in cancer tissu es, while 2 were up-regulated; 6 were of mid-high abundance and 2 were of l ow abundance in esophagus. The results revealed that alteration in expressi on level of multiple genes underlied the initiation and development of esop hageal cancer. The differentially expressed genes identified in this study such as liporcotin I, cystatin A, cystatin B, cytokeratin 13 may play roles in dedifferentiation, transformation and malignant proliferation of esopha geal cancer. The combination of SSH with PCR-based double-strand cDNA synth esis and high throughput reverse Northern screening is an efficient way to isolate differentially expressed genes from microgram of total RNA.