CCL2 and metastatic malignant neoplasm: As a result, it was shown that the genes COL3A1, SLPI, ITLN1 and CCL2 are expressed preferentially in MPM cells when compared with lung adenocarcinomas.73 Accordingly, significantly higher levels of secreted CCL2 were found in pleural effusions of MPM patients compared with pleural fluid from patients with other metastatic cancers or benign conditions.73