BAP1 and neoplasm: In summary, a tumor with a diameter of 11.1 mm and a thickness of 5.5 mm, which represents the average UM size at diagnosis, initiated 9.5 to 38.2 years before diagnosis, and its first cell with lost BAP1 expression appeared when the tumor was 0.5 to 4.6 years old, depending on the estimate of the proportion of tumor cells with loss of BAP1 expression in the average tumor and the mean time elapsed between mitoses.