 Matthew M. Yeh, MD, PhD, Anne M. Larson, MD,w Jean S. Campbell, PhD,  Nelson Fausto, MD, Stephen J. Rulyak, MD,w and Paul E. Swanson, MD

 Many risk factors for development of HCC are well known,Ex: chronic hepatitis and cirrhosis.  Underlying molecular mechanisms leading to hepatocarcinogenesis remain largely unclear.

 Transforming growth factor-a (TGF-a) is a mitogen 1)synthesized as a transmembrane polypeptide 2)cleaved to a 50 amino acid diffusible form

 bind the EGFR (epidermal growth factor receptor) and activate the signaling cascade from this receptor.

 Overexpression of TGF-a in the liver of transgenic mice induces increased proliferation, dysplasia, adenoma, and carcinoma.

 Previous studies have also confirmed the presence of TGF-a in a significant portion of HCC and adjacent liver.

 DNA topoisomerase II-a (Topo II-a) is a nuclear protein  targeted by several chemotherapeutic agents and has been shown to be overexpressed in HCC.

 Ki-67 is a nuclear protein that is detected in proliferating cells (late G1, S, G2, and M phase), but absent in resting cells (G0 phase).

 The expression of TGF-a or Topo II-a in dysplastic nodules has not been investigated.  most previous studies investigating the expression of TGF-a in HCC were performed in cirrhotic livers.

 examined the patterns of Ki-67, TGF-a, and Topo II-a expression in liver cirrhosis, low-grade dysplastic nodules (LGDN), HGDN, and HCC, using an immunohistochemical approach

 to define the possible relationships of these markers to tumor progression.  evaluated the difference in expression of TGF-a in HCC between cirrhotic and noncirrhotic livers.

 Explanted liver specimens from patients with cirrhosis who underwent liver transplantation surgery at the University of Washington Medical Center from 1989 to 2002 were retrospectively reviewed.

 Resected liver specimens in patients who underwent surgery for HCC at the University of Washington Medical Center from 1989 to 1992 were also retrospectively reviewed.

 The morphologic diagnoses of the liver lesions were confirmed by the consensus opinion of 2 pathologists (M.M.Y. and P.E.S.)  using the criteria published by the International Working Party(IWP).

 Monoclonal anti-TGF-a  Monoclonal anti-Topo II-a  monoclonal anti-Ki-67

 Immunohistochemical analyses were performed on representative sections of HCC, HGDN, LGDN, cirrhosis, and noncirrhotic liver parenchyma.

 The intensity of TGF-a immunostaining: graded by the 2 pathologists (M.M.Y. and P.E.S.) from 0 to 4.

 0-no staining;  1-focal weak staining in the hepatocytic cytoplasm;  2-diffuse weak staining in the hepatocytic cytoplasm;  3-diffuse weak and focal strong staining in the hepatocyticcytoplasm;  4-diffuse strong staining in the hepatocytic cytoplasm,

 The percentage of nuclei positive for Topo II-a and Ki-67  was obtained by manually counting 500 hepatocytes in the most intensively stained regions.

 in 52 cirrhotic livers from explanted or resected specimens: 46 HCC, 17 HGDN, and 12 low-grade dysplastic nodules were identified.  18 surgically resected cases of noncirrhoticliver with HCC were identified.

 The mean intensity score for TGF-a staining was 0.8 and 1.8 in HCC arising in the noncirrhotic and cirrhotic background, respectively (P=0.003).

 Most previously reported genomic and molecular studies have focused on fully developed HCC.

 postulated that the expression patterns of TGF-a,Ki-67, and Topo II-a should differ in the progression from cirrhosis through LGDN, HGDN to HCC.  Also compared the expression of TGF-a in HCC arising in cirrhotic livers with that of HCC arising in noncirrhotic livers.

 Ki-67’s expression has been considered a reliable index of proliferation.

 Increased proliferation has been observed in premalignant and malignant conditions of other organs, such as the stomach and esophagus.

 proliferation indices have been well- described in HCC.  Watanuki et al ---have reported a mean Topo II-a index of 14.1% in HCC, with a mean Ki-67 index of 25.6% in the same lesion.

 In the current study, ---Topo II-a and Ki-67 proliferative indices in HCC were similar to those of Watanuki and colleagues (18.9±10.4 and 26.1±13.6, respectively)

 Increased Topo II-a and Ki-67 protein expression in HCC correlates with decreased recurrence-free survival and earlier cancer-related death.

 Previous studies have shown that poorly differentiated HCC has more immunoreactivity to Ki-67 and Topo II-a than well or moderately differentiated HCC.

 In the current study, there was no significant difference in Ki-67 and Topo II- a staining between LGDN and the adjacent cirrhotic nodules.

 further study with expanded numbers will be necessary to better define the place of LGDN within the concept of stepwise progression.

 Overexpression of TGF-a in the livers of transgenic mice leads to the development of HCC.  Previous studies have demonstrated that human HCC expresses TGF-a as well

 The current study demonstrates that cirrhotic livers exhibit stronger expression of TGF-a when compared with noncirrhotic hepatic parenchyma.

 the intensity of TGF-a immunoreactivity in cirrhosis-associated HCC was stronger than that of HCC in noncirrhotic livers.

 there was also a decline in TGF-a expression from cirrhosis, through LGDN and HGDN to HCC.

 Kiss and colleagues: HBV-positive, higher proportion of HCC overexpressing TGF-a was observed compared with the HBV-negative group (21% and 6%, respectively).  suggesting that TGF-a as a role in human hepatocarcinogenesis may be etiology- dependent.

 the decrease in TGF-a expression from cirrhosis, through LGDN and HGDN to HCC supports the premise that TGF-a is more important to the early events in hepatocarcinogenesis.

 Although the relatively lower expression of TGF-a in HGDN and HCC seems counterintuitive (because overexpression of TGF-a in transgenic mice results in the development of dysplasia and HCC)

 we might plausibly argue that TGF-a is actively produced in cirrhotic liver and is gradually consumed in the process of hepatocarcinogenesis,  whereas other growth factors involved in the later stages of hepatocarcinogenesis may continue to be produced.

 Morimitsu et al ---have observed decreased expression of TGF-a in less differentiated HCC compared with well-differentiated HCC.

 Proliferative activity increases from cirrhosis to HCC, with HGDN showing an intermediate proliferative index. ---This finding provides another compelling line of evidence that HGDN is an advanced premalignant lesion in hepatocarcinogenesis.  TGF-a plays an early role in cirrhosis associated hepatocarcinogenesis and that this process may be etiology-dependent.