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.

 Peritoneal macrophages seem to participate in the process of peritoneal fibrosis and monocyte chemoattractant protein - 1 ( MCP - 1 ) plays a key role in the recruitment of monocytes toward the peritoneal cavity .
MCP - 1