Arginase-1 Is a More Sensitive Marker of Hepatic Differentiation Than HepPar-1 in Fine Needle Aspiration Biopsy Specimens.
Mika Fujiwara, Reetesh K Pai. Stanford University, CA
Background: Distinguishing hepatocellular carcinoma (HCC) from adenocarcinoma in fine needle aspiration biopsies (FNAB) is often diagnostically challenging. Arginase-1 was recently described as a marker of hepatic differentiation in surgical resection specimens. We compared the reactivities of Arginase-1 and HepPar-1 in FNAB of HCC and adenocarcinoma involving the liver.
Design: Seventy-four FNAB including 31 primary or metastatic HCC (27 well/moderately differentiated and 4 poorly differentiated) and 43 adenocarcinomas involving the liver were evaluated. Immunohistochemical staining for Arginase-1 (polyclonal, Sigma-Aldrich, 1:200) and HepPar-1 (clone OCH1E5, Dako, 1:200) was performed on formalin-fixed cell block material. Only cytoplasmic staining was scored as positive staining for both Arginase-1 and HepPar-1. Staining intensity (weak versus strong) and extent (focal, <10% versus diffuse, >10%) were scored.
Results: Arginase-1 was more sensitive (27/31, 87%) than HepPar-1 (25/31, 81%) for HCC (Table 1). Arginase-1 more often demonstrated strong (26/27, 96%) and diffuse (18/27, 67%) staining in HCC compared with HepPar-1 (20/25, 80% and 14/25, 56%, respectively). Arginase-1 staining was identified in adenocarcinomas of the pancreas, breast, and colorectal origin, although reactivity was typically weak and focal. HepPar-1 demonstrated strong and diffuse reactivity in cases of gastric, pulmonary, and prostatic adenocarcinoma.
|Tumor Type||Arginase-1 Positive (%)||HepPar-1 Positive (%)|
|Well/moderately differentiated HCC||25/27 (93)||24/27 (89)|
|Poorly Differentiated HCC||2/4 (50)||1/4 (25)|
|Colorectal and Anal carcinoma||2/16 (13)||0/16 (0)|
|Breast adenocarcinoma||1/12 (8)||0/12 (0)|
|Pancreatic adenocarcinoma||3/7 (43)||0/7 (0)|
|Pulmonary adenocarcinoma||0/3 (0)||1/3 (33)|
|Prostatic adenocarcinoma||0/2 (0)||1/2 (50)|
|Gastric adenocarcinoma||0/1 (0)||1/1 (100)|
|Intrahepatic cholangiocarcinoma||0/1 (0)||0/1 (0)|
|Uterine carcinoma||0/1 (0)||0/1 (0)|