Recent immunohistochemical markers in the differential diagnosis of primary and metastatic carcinomas of the liver

The strength of cytomorphology and efficacy of immuno-cytochemistry in distinguishing hepatocellular carcinoma from its mimics on fine-needle aspiration cytology

BACKGROUND

Cytomorphologic distinction of hepatocellular carcinoma (HCC) from its mimics on fine-needle aspiration cytology (FNAC) is often problematic. The present study evaluates the strength of cytomorphology and the utility of an immuno-panel of arginase-1, glypican-3, HepPar-1, thyroid transcription factor (TTF-1) and CK-19 in resolving this diagnostic issue.

METHODS

FNAC features of 71 nodular hepatic lesions were studied with an immunocyto/ histochemical (ICC/IHC) panel of arginase-1, glypican-3, HepPar-1, TTF-1 taking 10% positivity as "cut-off." Cytomorpholologic diagnoses were compared with diagnoses made on combined cytomorphologic and ICC/IHC approach.

RESULTS

Of 71 cases, 32, 10 and 29 had histopathologic, cell block and clinico-radiologic correlation respectively with 55 metastatic adenocarcinomas (MAC), 13 HCCs and one case each of hepatic adenoma (HA), cirrhotic nodule (CN) and intrahepatic cholangiocarcinoma (CC). Cytoplasmic positivity of HepPar-1 and glypican-3 were noted in 11/13 and 8/13 HCCs respectively; while only 3/13 and 1/13 HCCs revealed cytoplasmic positivity for arginase-1 and TTF-1 respectively. Benign hepatic lesions were negative for glypican-3 and TTF-1, but expressed both arginase-1and HepPar-1. Twenty-one of 55 MACs and the lone case of CC were positive for CK-19; however, all MACs and CC cases were negative for HepPar-1, arginase-1, glypican-3 and TTF-1. The immune-panel had sensitivity, specificity and diagnostic accuracy of 100%, 88.9% and 90.6%, respectively, for differentiating HCC from its morphologic mimics.

CONCLUSION

Though a meticulous cytologic evaluation in conjunction with clinicoradiologic profile helps in distinguishing HCC from its benign and malignant mimics; an immunopanel of arginase-1, glypican-3, HepPar-1, TTF-1 and CK-19 drastically improves the diagnostic accuracy.

Immunohistochemical and Biochemical Expression Patterns of TTF-1, RAGE, GLUT-1 and SOX2 in HCV-Associated Hepatocellular Carcinomas

Objective:

To investigate the expression of TTF-1, RAGE, GLUT1 and SOX2 in HCV-associated HCCs and in surrounding non-tumorous liver tissue.

Material and Methods:

Tissue material from partial hepatectomy cases for HCC along with corresponding serum samples and 30 control serum samples from healthy volunteers were studied. Biopsies were classified into: non-tumor hepatic tissue (36 sections); HCC (33 sections) and liver cell dysplasia (LCD) (15 sections). All cases were positive for HCV. Immunohistochemistry (IHC), gene extraction and quantitative real-time reverse-transcription assays (qRT-PCR) were applied.

Results:

By IHC, LCD and HCC showed significantly high percentages of positive cases with all markers. SOX2 showed significant increase with higher HCC grades, while RAGE demonstrated an inverse relation and GLUT-1 and TTF-1 lacked any correlation. In nontumorous-HCV tissue, we found significantly high TTF-1, low RAGE and negative SOX2 expression. RAGE, GLUT-1 and SOX2 show non-significant elevation positivity in high grade HCV compared to low grade lesions. TTF-1, RAGE and SOX2 exhibited low expression in cirrhosis compared to fibrosis. Biochemical studies on serum and tissue extracts revealed significant down-regulation of RAGE, GLUT-1 and SOX2 genes, as well as significant up-regulation of the TTF-1 gene in HCC cases compared to controls. All studied genes show significant correlation with HCC grade. In non-tumor tissue, only TTF-1 gene expression had a significant correlation with the fibrosis score.

Conclusion:

Higher expression of TTF-1, RAGE, GLUT-1 and SOX2 in HCC and dysplasia compared to non-tumor tissues indicates up-regulation of these markers as early events during the development of HCV-associated HCC.

Telecytological diagnosis of space-occupying lesions of the liver

OBJECTIVE

In this study, the efficiency of telemedical consulting with regard to fine needle aspirates from space-occupying lesions (SOLs) of the liver is investigated for the first time.

STUDY DESIGN

The study includes fine needle aspirations from 62 patients, 33 with hepatocellular carcinoma (HCC) and 29 with non-hepatic tumors. Using the Internet-based iPath system, the initial pathologist submitted 1-8 images from smears and cell block sections. One consultant assessed the cytological and another one the histological images. Both made their diagnoses independent of each other. A final diagnosis was made by immunochemistry of cell block sections. The cytological images were analyzed retrospectively for the occurrence of the most typical HCC indicators. The number of these indicators was related to the initial diagnoses of the three pathologists, and possible reasons for diagnostic errors were analyzed based on this analysis.

RESULTS

The accuracy of the preliminary telemedical diagnoses regarding HCC was 82.0% for the cytological images and 87.7% for the histological images. Most of the false diagnoses occurred in tumors with unusual cytological and histological patterns.

CONCLUSIONS

Telemedical consulting is a valuable tool to obtain a second opinion. However, for improvement of the diagnosis of HCC, supplementary immunochemical tests are necessary.

HepPar-1 expression in primary lung adenocarcinoma

OBJECTIVES

To study a subset of lung adenocarcinomas with aberrant HepPar-1 antigen expression.

METHODS

We performed a clinicopathologic review of 16 cases.

RESULTS

Of 241 primary lung adenocarcinomas tested for expression of the HepPar-1 antigen, 16 (6.6%) were positive. The cases occurred in older smokers with an equal sex distribution. Morphologically, these pulmonary adenocarcinomas had an acinar-predominant architecture, and prominent cribriform growth, with HepPar-1-expressing tumor cells being uniformly columnar with abundant bipolar lightly eosinophilic cytoplasm. HepPar-1 was coexpressed with thyroid transcription factor 1 in 94% of cases. No EGFR mutations were identified, while 31% of cases were positive for KRAS codon 12 mutations.

CONCLUSIONS

Although aberrant HepPar-1 expression was frequently seen in tumors with visceral pleural and angiolymphatic invasion, its prognostic significance is uncertain.

Cytoplasmic staining of TTF-1 in the differential diagnosis of hepatocellular carcinoma

Thyroid transcription factor 1 (TTF-1) is a widely used biomarker in surgical pathology. Its nuclear staining is sensitive and specific for the diagnosis of primary pulmonary and thyroid adenocarcinoma as well as small cell carcinomas arising in many organs. The cytoplasmic staining of TTF-1 is also observed, particularly in the benign and malignant hepatic cells. It has been controversial whether TTF-1 cytoplasmic staining is reliable enough to have diagnostic value. This review focuses on this issue and explores the potential application of TTF-1 cytoplasmic staining in the differential diagnosis of hepatocellular carcinoma from other primary and metastatic malignancies in the liver. The mechanism of TTF-1 cytoplasmic staining is also discussed.

Value of thyroid transcription factor-1 immunostaining in tumor diagnosis: a review and update

Thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor that plays a critical role in the normal development of embryonic epithelial cells of the thyroid and lung. Because TTF-1 expression is highly restricted to epithelial tumors arising in these organs, it is, at present, one of the immunohistochemical markers most commonly used to assist in the differential diagnosis of carcinomas of the lung and thyroid. Recent studies, however, have reported that TTF-1 is not as specific for lung and thyroid carcinomas as was previously thought as it can be found to be expressed, although much less frequently, in some carcinomas arising in other organs, such as the ovaries, endometrium, colon, and breast, as well as in some tumors of the central nervous system. Even though this unexpected TTF-1 positivity has been reported more frequently with the recently available SPT24 anti-TTF-1 monoclonal antibody, it has also been shown to occur with the commonly used 8G7G3/1 clone, albeit in a lower percentage of cases. Despite these findings, TTF-1 remains a very useful immunohistochemical marker in diagnostic pathology.

Fine needle aspiration biopsy of hepatocellular carcinoma and hepatocellular nodular lesions: role, controversies and approach to diagnosis

The role of fine needle aspiration (FNA) biopsy of the liver has evolved. Advances in imaging modalities have obviated the need for tissue confirmation in clinically classic hepatocellular carcinoma (HCC). The risks of needle tract seeding and haematogenous dissemination have been actively debated. Nowadays, cytopathologists are confronted by smaller and smaller nodules, detected due to increased surveillance of high-risk cirrhotic patients. Tissue characterization of small well-differentiated hepatocellular nodular lesions (size less than and equal to 2 cm) is extremely challenging and has therapeutic implications. Major issues in the cytodiagnosis of HCC include: (i) distinguishing benign hepatocellular nodular lesions, namely, large regenerative nodules, dysplastic nodules, focal nodular hyperplasia and hepatocellular adenoma from reactive hepatocytes; (ii) distinguishing well-differentiated HCC from benign hepatocellular nodular lesions; (iii) distinguishing poorly differentiated HCC from intrahepatic cholangiocarcinoma and metastatic carcinomas; (iv) determining the histogenesis of a malignant tumour; and (v) determining the site of origin of a malignant tumour. An overview of the biological evolution and histopathological aspects of dysplastic nodules, small HCCs and 'nodule-in-nodule' lesions is presented in tandem with clinically relevant nomenclature. An algorithmic approach to FNA diagnosis of HCC and hepatocellular nodular lesions is outlined. Optimal results depend on (i) a dedicated radiologist-cytopathologist team; (ii) an on-site cytology service, (iii) a combined cytohistological approach, (iv) immunohistochemistry, and (v) clinicopathological correlation. As we move towards personalized medicine, it is envisaged that hepatic FNA is likely to become a point of care in the management protocol as it takes on the additional role of procurement of tumour and peritumoural tissues for genomic and proteomic profiling to enable targeted molecular therapy.

Fine-needle aspiration biopsy of hepatocellular carcinoma and related hepatocellular nodular lesions in cirrhosis: controversies, challenges, and expectations

The role of hepatic fine-needle aspiration (FNA) biopsy has evolved. Advances in imaging modalities have obviated the need for tissue confirmation in most hepatocellular carcinomas (HCCs). There is risk of needle-tract seeding. Increasingly, small nodules are being detected on ultrasound surveillance of high-risk patients. Diagnostic challenges associated with cirrhosis include distinction of benign hepatocellular nodules, namely, large regenerative nodules and dysplastic nodules, from reactive hepatocytes; and distinction of well-differentiated HCCs from benign hepatocellular nodules. This paper will discuss (i) controversies regarding preoperative/pretransplantation FNA diagnosis of HCC, (ii) update of biological evolution, nomenclature, and histopathologic criteria for diagnosis of precancerous nodules and small HCCs, and (iii) algorithmic approach to FNA diagnosis of hepatocellular nodules. Optimal results depend on dedicated radiologist-cytopathologist team, on-site cytology service; combined cytohistologic approach, immunohistochemistry, and clinicopathologic correlation. Hepatic FNA is likely to be incorporated as a point of care as we move towards personalized medicine.

The best immunohistochemical panel for differentiating hepatocellular carcinoma from metastatic adenocarcinoma

It can be difficult to differentiate hepatocellular carcinoma (HCC) from metastatic adenocarcinoma (MA). An appropriate immunohistochemical panel is required for the differential diagnosis. This study aimed at finding the best panel, including hepatocyte-specific antigen (Hepatocyte), pCEA, CD10, Villin, CD34, TTF-1, MOC-31, CK7, and CK20 antibodies. Sixty-eight cases of HCC and 107 cases of MA were investigated. Hepatocyte positivity was seen in 95.6% of HCCs and in 1.9% of MAs. pCEA was expressed in 47.8% of HCCs and in 86.8% of MAs. CD10 stained 73.13% of HCCs and 36.9% of MAs. Villin was positive in 23.5% of HCCs and in 81.0% of MAs. Canalicular staining with pCEA, CD10, and Villin was seen only in HCCs. Sinusoidal CD34 staining was seen only in 42.6% of HCCs. A small subset of HCCs demonstrated cytoplasmic TTF-1 and MOC-31. CK7 was expressed in 29.4% of HCCs and in 29.9% of MAs, whereas CK20 stained 14.7% of HCCs and 62.6% of MAs. In conclusion, Hepatocyte should be combined with pCEA, MOC-31, CD10, and CD34. Canalicular staining with pCEA, CD10, and Villin is specific for HCC. CK7 and CK20 expression may be seen in some HCCs. We suggest that the best panel for discriminating HCC from MA should contain Hepatocyte, MOC-31, pCEA, CD10, and CD34.

Natural killer cells play a key role in the antitumor immunity generated by chaperone-rich cell lysate vaccination

Tumor derived chaperone-rich cell lysate (CRCL) when isolated from tumor tissues is a potent vaccine that contains at least 4 of the highly immunogenic heat shock proteins (HSP) such as HSP70, HSP90, glucose related protein 94 and calreticulin. We have previously documented that CRCL provides both a source of tumor antigens and danger signals triggering dendritic cell (DC) activation. Immunization with tumor derived CRCL elicits tumor-specific T cell responses leading to tumor regression. In the current study, we further dissect the mechanisms by which CRCL simulates the immune system, and demonstrate that natural killer (NK) cells are required for effective antitumor effects to take place. Our results illustrate that CRCL directly stimulates proinflammatory cytokine and chemokine production by NK cells, which may lead to activation and recruitment of macrophages at the tumor site. Thus, this report provides further insight into the function of CRCL as an immunostimulant against cancer.