Identification of a novel gene, selectively up-regulated in human carcinomas, using the differential display technique.

Using the differential display technique, selecting for genes up-regulated in renal cell carcinoma compared with normal renal parenchyma, we isolated a novel gene, designated DD96. As determined by in situ and Northern blot hybridization studies, DD96 is expressed only in rare normal epithelial cell populations, such as the proximal tubular epithelial cells of the kidney. However, it is expressed diffusely in malignant epithelial cells of the wide majority of renal cell carcinomas. In addition, DD96 is overexpressed markedly in various human carcinomas originating from the colon, breast, and lung, as well as in a number of cell lines derived from tumors of these organs compared with normal epithelial cell populations. Furthermore, the expression of DD96 is induced in immortalized breast ductal epithelial cell lines compared with normal breast ductal epithelial cells, and, in vivo, in premalignant conditions, such as adenoma of the colon and ductal carcinoma in situ of the breast. Sequence analysis of a complete cDNA clone isolated from a human kidney cDNA library revealed that DD96 encodes for a protein of approximately Mr 13,500. These results suggest that DD96 may play a role in the early events associated with malignant transformation; however, its function remains to be determined.