Jianzhou Wang

mTOR and P70 S6 Kinase Expression in Primary Liver Neoplasms

Purpose: mTOR and P70 S6 kinase (S6K) play a key role in regulating protein translation. The role of mTOR and S6K in hepatocellular carcinoma has not been investigated, but this pathway is of particular interest because an effective inhibitor, rapamycin, is available. This study was undertaken to determine the prevalence and clinicopathological correlates of mTOR pathway activation in hepatocellular carcinoma and to determine whether rapamycin inhibits the pathway in cell culture. Experimental Design: Total and phosphorylated mTOR and S6K protein expression were studied by immunohistochemistry in hepatocellular carcinomas (n = 73), fibrolamellar carcinomas (n = 13), and hepatic adenomas (n = 15). Results were correlated with tumor growth pattern as defined by the WHO (trabecular, pseudoglandular/acinar, compact, and scirrhous), tumor size, Ki-67 proliferation index, and the modified Edmondson nuclear grade, which has a scale of 1 to 4. HepG2 and Hep3B cell lines were treated with rapamycin to see the effect on proliferation and S6K phosphorylation. Results: Increased expression of total mTOR was seen in 5% of hepatocellular carcinoma, whereas overexpression of phospho-mTOR was evident in 15% of hepatocellular carcinoma. Phospho-mTOR positivity correlated with increased expression of total S6K, which was found in 45% of cases. Total S6K overexpression was positively correlated with tumor nuclear grade, inversely with tumor size, and was unassociated with the proliferation index or WHO growth pattern. Rapamycin treatment of HepG2 and Hep3B cell lines markedly inhibited cell proliferation and reduced S6K phosphorylation in both cell lines. Conclusions: The mTOR pathway is activated in a subset of hepatocellular carcinoma. Rapamycin can inhibit proliferation of neoplastic hepatocytes in cell culture.

Survivin overexpression in hepatocellular carcinoma is associated with p53 dysregulation

AbstractBackground: Survivin is a recently described anti-apoptotic protein that is suppressed by wild-type p53 and is overexpressed in 41–70% of hepatocellular carcinomas from Asia. Two alternatively spliced transcripts have also been described: anti-apoptotic survivin-ΔEx3 and non—anti-apoptotic survivin-2B. Survivin splice variant expression has not been studied in HCC, and little is known about survivin expression in hepatocellular carcinomas arising in other parts of the world, where risk factors are often different than they are in Asia. Aim of the Study: We studied survivin mRNA and protein expression in a United States cohort of hepatocellular carcinomas and correlated the findings with p53 immunopositivity. Methods: RT-PCR was performed for survivin, survivin-2B, and survivin-ΔEx3 in 20 HCCs and one intrahepatic cholangiocarcinoma. Expression levels of total survivin were evaluated with real-time PCR. Protein expression was examined by immunohistochemistry. Results: Survivin was the major transcript, and all transcripts were present in all normal and neoplastic tissues; 11/20 (55%) HCCs and the one cholangiocarcinoma showed twofold or greater overexpression of survivin. Next, we examined survivin and p53 protein expression by immunohistochemistry on a separate series of 79 HCC, 13 fibrolamellar carcinomas, and 15 hepatic adenomas; 14/79 (17%) HCC, but none of the fibrolamellar carcinomas or hepatic adenomas, showed survivin protein overexpression, and 25/79 HCC (32%) showed abnormal nuclear accumulation of p53, which correlated with increased survivin expression. Conclusions: All three survivin transcripts are present in normal liver and HCC. Survivin is the dominant transcript in HCC and is overexpressed in 55% of cases. Survivin protein overexpression is associated with aberrant p53 nuclear positivity.

Bile ducts and ductules are positive for CD56 (N-CAM) in most cases of extrahepatic biliary atresia.

The diagnosis of extrahepatic biliary atresia can be challenging as the histologic features can overlap with other pediatric cholestatic liver diseases. Several previous studies have noted that biliary epithelium is positive for CD56 in the setting of extrahepatic biliary tract disease. Thus, we explored the use of CD56 in evaluating liver biopsy specimens for extrahepatic biliary atresia. A total of 22 cases were selected and immunostained for CD56, including 14 cases of confirmed extrahepatic biliary atresia and 8 cases of other cholestatic liver diseases in which the differential diagnosis included extrahepatic biliary atresia. Bile ducts and proliferating ductules were positive for CD56 in 13 of 14 cases of extrahepatic biliary atresia. The staining intensity was generally strong with most cases showing positivity in more than two thirds of portal tracts. The one negative case was a very small biopsy (<0.3 cm), and sampling may have played a role. In contrast, 4 of 8 cases in the control group were completely negative for CD56, with the remaining cases showing weak and focal positivity. In conclusion, bile ducts and ductules are CD56 positive in most cases of extrahepatic biliary atresia, and CD56 immunostaining can be a useful supplemental stain for diagnosing extrahepatic biliary atresia in its early, ductular proliferative phase when used in conjunction with traditional hematoxylin and eosin morphology and clinical information.

Concurrent Evaluation of p53, β-Catenin, and α-Fetoprotein Expression in Human Hepatocellular Carcinoma

Recent models suggest that hepatocellular carcinoma (HCC) develops through several independent pathways marked by key mutations in the β-catenin or p53 gene. An additional pathway potentially is marked by aberrant expression of α-fetoprotein (AFP). To see whether these potential markers are expressed independently, we immunostained sequential sections from 55 HCCs. Of the cases, 30 (55%) were positive for 1 or more proteins: AFP, 19 cases (35%); p53, 12 cases (22%); and β-catenin, 9 cases (16%). Seven tumors (13%) were positive for more than 1 protein, with 4 of 7 positive in the same area of tumor and 3 of 7 positive in different areas of the carcinomas. By statistical analysis, expression of the markers was independent of one another and of tumor size. Concurrent evaluation of p53, β-catenin, and AFP protein expression showed no associations, supporting models in which these proteins might serve as markers of independent pathways in the development of HCC.

Expression of cadherins and catenins in paired tumor and non-neoplastic primary prostate cultures and corresponding prostatectomy specimens

Abstract Cadherins are a family of transmembrane proteins that play a crucial role in cell differentiation, cell migration, and intercellular adhesion. Cadherins are associated with catenins through their highly conserved cytoplasmic domain. Down-regulation of E-cadherin protein has been shown in various human cancers. This study examined the expression of cadherins and associated catenins at the mRNA level. Paired tumor and non-neoplastic primary prostate cultures were obtained from surgical specimens. Quantitative multiplex fluorescence reverse transcriptase-polymerase chain reaction (QMF RT-PCR) and quantitative analysis were performed and correlated with immunostain results. Six of seven cases of neoplastic cultures showed moderately-to-markedly decreased levels of E-cadherin and P-cadherin mRNA. Similar losses of α-catenin and β-catenin mRNA were also observed. The results of QMF RT-PCR showed good correlation with the results of immunohistochemical studies based on corresponding formalin-fixed sections. In conclusion, this paper presents a coordinated down-regulation in the expression of E-cadherin and associated catenins at the mRNA and protein level in most of the cases studied. This down-regulation may play an important role in the pathogenesis of prostate cancer.

Loss of SDHB and NF1 genes in a malignant phyllodes tumor of the breast as detected by oligo-array comparative genomic hybridization

We report oligo-array comparative genomic hybridization findings in a case of malignant phyllodes tumor of the breast. In addition to gains of 1q and 5p, and losses of 10p and 13q14 approximately q22, this tumor had also losses of two regions to which tumor suppressor genes are mapped: 1p36 (SDHB) and 17q11.2 (NF1). Both genes are associated with hereditary cancer syndromes, including gastrointestinal stromal tumors. Whether these two genes played a role in the development or progression of this phyllodes tumor of the breast with a sarcomatous stromal component warrants further investigation of similar cases.

Uterine tumor resembling ovarian sex cord tumor: report of a case with t(X;6)(p22.3;q23.1) and t(4;18)(q21.1;q21.3).

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare tumor of reproductive-age and postmenopausal women. We present the first case of UTROSCT with cytogenetic analysis. The tumor occurred in a 34-year-old woman who presented with menorrhagia and a uterine mass. Histologic examination showed tumor with features of sex cord-like epithelium and abundant fibromuscular stroma without an endometrial stromal sarcoma component. The tumor cells expressed cytokeratin, CD99, vimentin, desmin, smooth muscle actin, and estrogen and progesterone receptors. The majority of the cells analyzed by cytogenetic studies showed two balanced chromosomal translocations: t(X;6)(p22.3;q23.1) and t(4;18)(q21.1;q21.3). Several known tumor-related genes (bcl-2, MALT-1, FVT1, SCCA1, SCCA2, and DCC at 18q21; RAP1 at 4q21; and STL at 6q23) and a gonadal-development related gene (H-Y regulator gene at Xp22.3) are located at or near the translocation breakpoints. The tumor cells of sex cord–like elements were strongly and diffusely immunoreactive for bcl-2 antibody. These cytogenetic and immunohistochemical data may suggest potential molecular mechanisms of tumorigenesis of UTROSCT.

Occult nonhematopoietic malignancies present at autopsy in solid organ transplant patients who died within 100 days.

Background. Patients are at an increased risk for developing malignancies after transplantation. Lymphomas, skin malignancies, Kaposi’s sarcomas, and cervical/vulvar neoplasms are the most common, but visceral malignancies are also well documented, with a reported frequency ranging from 1% to 6%. These visceral tumors represent a mix of neoplasms that were clinically occult at the time of transplantation and those that arise de novo after transplantation. Little information, however, is available on the frequency of clinically occult malignancies at the time of transplantation and their contribution to the number of posttransplant malignancies. Methods. A retrospective study was performed of all patients who received an organ transplant from January 1981 to June 1997 and died within 100 days, a time interval in which epithelial malignancies found at autopsy were presumed to have been present, but clinically occult, at the time of transplantation. Results. A total of 375 patients were studied who received the following organ transplants: 231 liver, 52 heart, 26 heart and lung, 32 lung, and 34 kidney. Eleven malignancies were identified for an overall frequency of 2.9% and included three thyroid carcinomas, three carcinoids of the small bowel, two lung carcinomas, one laryngeal carcinoma, one renal cell carcinoma, and one seminoma. Conclusion. The 2.9% frequency of malignancies seen in this study suggests that a small, but significant, number of patients have occult malignancies at the time of transplantation and that these occult tumors contribute substantially to the number of malignancies that present clinically after transplantation.

RENAL CORTICAL NEOPLASMS IN LONG TERM SURVIVORS OF SOLID ORGAN TRANSPLANTATION

BACKGROUND Renal cortical neoplasms have been reported after organ transplantation, but the level of risk as well as the histological features are poorly defined. METHODS A retrospective autopsy-based study was performed to evaluate renal neoplasms occurring in patients who underwent solid organ transplantation, died, and received an autopsy from 1981 to 1997 (383 liver, 125 heart, 52 lung, 39 heart/lung, 98 kidney, 4 bowel). Patients were divided into those with short (less than 101 days), medium (101 days to 5 years), and long-term survival (more than 5 years). The control group consisted of hospital autopsies on nontransplanted patients from the odd-numbered years, 1983 through 1997. RESULTS Renal cortical neoplasms were identified in 32/1325 of nontransplanted patients and 15/701 transplanted patients. In transplanted patients, neoplasms were identified in 14 native and 1 allograft kidney: 2/391 in short-term survivors, 3/234 in medium, and 10/76 in long term survivors. While transplant patients with short and medium length survival had no increased risk for neoplasms, patients with long-term survival showed a 9-fold increase in cortical neoplasms. Transplant patients with neoplasms averaged 47 years of age at death, significantly younger than the average age of 70 for nontransplanted control patients with renal neoplasms. The neoplasms in transplanted patients were all tubulopapillary, except for one clear cell neoplasm and ranged in size from 0.1 to 2 cm. CONCLUSIONS Long-term survivors of solid organ transplants have an 9-fold increased risk of developing tubulopapillary renal cortical neoplasms.