SUSCEPTIBILITY TO ULTRAVIOLET-INDUCED CORNEAL SARCOMAS IS HIGHLY HERITABLE IN A LABORATORY OPOSSUM MODEL

The laboratory opossum, Monodelphis domestica, develops hyperplasia an d neoplasia of the corneal stroma after repeated exposure to low doses of ultraviolet radiation (UVR) (non-erythemic in skin). We exposed ad ult animals from genetically diverse families within our colony to det ermine whether there are any heritable components to the risk of this form of eye cancer. From about 5 months of age, animals were exposed 3 times a week to a dose of about 125 J/m(2) of UVB (spectral peak = 30 2 nm). Thirty-three sibships (151 individuals) completed at least 30 w eeks of the protocol and 137 individuals completed 45 weeks. For genet ic analysis, each animal was classified at 30 and 45 weeks as affected with corneal sarcoma or not. Heritabilities were estimated for the di chotomous eye-tumor trait which was highly heritable at both time poin ts. This eye-cancer model system is valuable as a source of material f or in vitro studies of angiogenesis and neoplastic transformation, for in vivo studies of tumor therapy and prevention, and for further rese arch on the genetic determinants of cancer. (C) 1994 Wiley-Liss, Inc.