Expression of heat shock proteins (HSP27, HSP60, HSP70, HSP90, GRP78, GRP94) in hepatitis B virus-related hepatocellular carcinomas and dysplastic nodules

Abstract

Aim: Expression of heat shock proteins (HSPs) is frequently up-regulated in hepatocellular carcinoma (HCC), which evolves from dysplastic nodule (DN) and early HCC to advanced HCC. However, little is known about the differential expression of HSPs in multistep hepatocarcinogenesis. It was the purpose of this study to monitor the expression of HSPs in multistep hepatocarcinogenesis and to evaluate their prognostic significance in hepatitis B virus (HBV)-related HCC.

Methods: Thirty-eight HCC and 19 DN samples were obtained from 52 hepatitis B surface antigen-positive Korean patients. Immunohistochemical and dot immunoblot analyses of HSP27, HSP60, HSP70, HSP90, glucose regulated protein (GRP)78, and GRP94 were performed and their expression at different stages of HCC development was statistically analyzed.

Results: Expression of HSP27, HSP70, HSP90, GRP78, and GRP94 increased along with the stepwise progression of hepatocarcinogenesis. Strong correlation was found only in GRP78 (Spearman's r = 0.802). There was a positive correlation between the expressions of GRP78, GRP94, HSP90, or HSP70 and prognostic factors of HCC. Specifically, the expression of GRP78, GRP94, or HSP90 was associated significantly with vascular invasion and intrahepatic metastasis.

Conclusion: The expressions of HSPs are commonly up-regulated in HBV-related HCCs and GRP78 might play an important role in the stepwise progression of HBV-related hepatocarcinogenesis. GRP78, GRP94, and HSP90 may be important prognostic markers of HBV-related HCC, strongly suggesting vascular invasion and intrahepatic metastasis.

Figure 1

IHC staining of HSP in DN and HCC (original magnification, ×100). A: Rare immunoreactivity for HSP27 in high-grade DN; B: 25% immunoreactivity for HSP27 in early HCC. The borders between early HCC and non-tumorous liver are indicated by arrowheads; C: 96% immunoreactivity for HSP60 in HCC Grade II; D: 30% immunoreactivity for HSP70 in HCC Grade I. Bile duct epithelium shows cytoplasmic immunoreactivity (arrow); E: 35% immunoreactivity for HSP90 in HCC Grade II; F: Rare immunoreactivity for GRP78 in low-grade DN; G: 10% immunoreactivity for GRP78 in HCC Grade I; H: 93% immunoreactivity for GRP78 in HCC Grade III; I: 15% immunoreactivity for GRP94 in high-grade DN; J: 95% immunoreactivity for GRP94 in HCC Grade III. N, non-tumorous liver.

Figure 2

Examples of dot immunoblot and immunoblot analysis of HSP27 in the same tissue samples. A: Dot immunoblot analysis of HSP27 in tumor (T) and non-tumorous tissue (N) of 15 patients (LGDN, six; HGDN, three; E-HCC, four; HCC GI, two cases); B: Immunoblot analysis of HSP27 in tumor and non-tumorous tissue of 15 patients. Dot immunoblotting and immunoblotting with HSP27 monoclonal antibody were performed as described in Materials and Methods. β-actin was used as a reference. The results of dot immunoblot analysis revealed the same expression patterns as the immunoblot analysis. LGDN: low-grade dysplastic nodule, HGDN: high-grade dysplastic nodule, E: early, HCC: hepatocellular carcinoma, G: Edmondson-Steiner’s grade.