Expression of p21 super(ras) in normal and malignant human tissues: Lack of association with proliferation and malignancy

Proteins encoded by cellular ras oncogenes (p21 super(ras)) are expressed in a wide variety of malignant tumors. This immunohistochemical study examined the relationship between p21 super(ras) expression and malignant transformation, cellular differentiation, and proliferative activity in vivo. p21 super(ras) was found to be widely expressed in normal tissues. Terminally differentiated cells generally showed stronger reactivity with antibodies to p21 super(ras) than did rapidly proliferating cells. Fetal and adult tissues had corresponding patterns of p21 super(ras) expression, and the distribution of p21 super(ras) in neoplasms paralleled the pattern in normal tissue from which they were derived.