SAA2 and neoplasm: To evaluate whether the high SAA expression detected by flow cytometry on primary USPC cell lines was compared with the expression of SAA of the USPC specimens from which the primary tumour cell lines were derived (i.e., USPC-ARK-1, USPC-ARK-2, and USPC-ARK-3) and/or whether in vitro expansion conditions may have modified protein expression, we evaluated SAA by immunohistochemical staining on formalin-fixed tumour tissue.