TPMT and cancer: In each of these patient populations there have been a number of reports of cancer development after thiopurine therapy to include acute myeloid leukemias, lymphomas, and cancers of the skin and brain [8], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24]; although, the relevance of Tpmt status is not clear.