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: The activation of this signaling pathway requires functional CD4 receptors and is independent of binding to CXCR4 .
Example Output: CD4 receptors

Example Input: Receptor cleavage by these and other endogenous enzymes may account for previous observations of ' ' abnormal ' ' receptors in cytosols from some leukemic specimens .
Example Output: endogenous enzymes

Example Input: Immunoglobulin gene - specific transacting factors have been shown to play a role in lymphoid tissue - specific expression of immunoglobulin genes .
Example Output:
immunoglobulin genes