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.

Example Input:  In this study , we examined whether PPARgamma ligand regulates osteopontin gene expression in THP - 1 cells , a cell line derived from human monocytic leukemia cells which can differentiate to macrophage upon stimulation with phorbol ester PMA .
Example Output: PPARgamma ligand

Example Input:  Ultraviolet - B - induced DNA damage is repaired by the nucleotide excision repair mechanism very efficiently .
Example Output: - B

Example Input:  One of the challenges in defining the molecular events regulated by Nef has been obtaining good expression of Nef protein in T cells .
Example Output:
Nef protein