ARL11 and prostate carcinoma: Although limited, a few studies suggest that ARLTS1 expression is downregulated in various types of human malignant disease, including prostate cancer,14 lung carcinomas, B cell chronic lymphocytic leukemia, ovarian carcinomas, and ovarian and breast cancer cell lines.4 The limited number of studies demonstrating ARLTS1 expression makes it difficult to comment further on this issue.