Experimental Malignant Tumors From Retinal Pigment Epithelium

Malignant neoplasms of the retinal pigment epithelium (RPE) were produced by infecting pure cultures of hamster RPE in vitro with simian vacuolating virus 40, an oncogenic DNA virus. When transformed cells were injected subcutaneously into irradiated 4-week-old hamsters, neoplasms developed at the injection site within three weeks and subsequently killed the animals by generalized metastasis. These experimental tumors resembled morphologically some tumors seen in human eyes arising from the RPE. While extraocular invasion or metastasis of human RPE tumors has not been documented convincingly, this study demonstrates that under experimental conditions retinal pigment can give rise to tumors capable of invasion and metastasis and provides a model useful in distinguishing histologic characteristics of true malignant tumors of the RPE.