Given the task definition and input, reply with output. In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

 By contrast , subcapsular immature double - negative ( DN ) ( CD4 ( - ) / CD8 ( - ) ) T cells in the thymus coexpressed BMI - 1 and EZH2 or were BMI - 1 single positive .

BMI - 1