As a common explanation, immunity related to human mucin 1 could explain the risk for not only ovarian, breast, and endometrial cancers but also other MUC1-expressing cancers that have been targets of MUC1 vaccine trials (104), such as colorectal cancer and lung cancer, and point to the possible relevance of ovulatory cycles to their epidemiology. This evidence concerns the gene MUC1 and lung carcinoma.