Paul Chih-Hsueh Chen

KIT (CD117) is frequently overexpressed in thymic carcinomas but is absent in thymomas.

KIT (CD117), a tyrosine kinase receptor, has not been widely studied in epithelial tumours. In a systematic immunohistochemical survey of KIT expression on tissue arrays incorporating 671 cases, it was found that thymic carcinomas frequently express KIT. Twenty‐two thymic carcinomas, 110 thymomas, and 16 non‐neoplastic thymus glands were retrieved for further analyses. Immunohistochemically, 19 (86%) thymic carcinomas revealed heterogeneous to diffuse membranous positivity, whereas no thymomas or normal thymus glands contained positive epithelial cells. Using reverse transcriptase‐polymerase chain reaction (RT‐PCR), c‐kit transcripts could be demonstrated in all immunohistochemically positive cases. PCR amplification and direct sequencing of the c‐kit juxtamembrane domains (exons 9 and 11) and tyrosine kinase domain (exons 13 and 17) were also performed on the thymic carcinomas but mutations were not found. Some non‐thymic epithelial tumours showed frequent KIT expression including adenoid cystic carcinomas of the salivary gland (100% positive), chromophobe renal cell carcinomas (94%), renal oncocytomas (67%), and neuroendocrine tumours (34%). Other carcinomas were infrequently immunoreactive for KIT. The findings of this study suggest that KIT is involved in the pathogenesis of thymic carcinomas. The overexpression of KIT in thymic carcinomas has potential diagnostic utility in differentiating these tumours from thymomas and carcinomas arising from other sites, which express KIT infrequently. Copyright

Constant allelic alteration on chromosome 16p (TSC2 gene) in perivascular epithelioid cell tumour (PEComa): genetic evidence for the relationship of PEComa with angiomyolipoma†

Perivascular epithelioid cell tumours (PEComas) are a family of tumours including classic angiomyolipoma, lymphangioleiomyomatosis, and clear epithelioid cell tumours reported under a variety of names such as epithelioid angiomyolipoma, pulmonary and extrapulmonary clear cell sugar tumour, and PEComa. Our previous comparative genomic hybridization study of PEComas demonstrated recurrent chromosomal aberrations including deletions on chromosome 16p, where the TSC2 gene is located. In this study, we focused on the alteration of chromosome 16p, including TSC2. We collected ten sporadic and two tuberous sclerosis complex‐associated PEComas, as well as 14 sporadic classic hepatic and renal angiomyolipomas (AMLs) as controls. We used 16 microsatellite markers distributed along chromosome 16p to test for allelic imbalances on chromosome 16p and at TSC2, and two markers for TSC1. Furthermore, we carried out immunohistochemical staining for phospho‐p706K, phospho‐AKT, and phospho‐S6 to evaluate the effect of TSC2 alterations on the mTOR signalling pathway. Loss of heterozygosity (LOH) was found in 11 PEComas and involved the region of the TSC2 locus in seven. Six classic angiomyolipomas had allelic changes at chromosome 16p. Microsatellite instability was detected in two PEComas. The incidence of genetic aberrations was significantly higher in the PEComa group. Only one PEComa showed LOH at the TSC1 locus. Eleven PEComas and 13 AMLs revealed elevated phospho‐p70S6K accompanied by reduced phospho‐AKT. Five PEComas and eight classic angiomyolipomas were positive for phospho‐S6. The phosphorylation profile indicates functional activation of the mTOR pathway through a disrupted TSC1/2 complex. Our observations of frequent deletion of TSC2 and the mTOR signalling pathway provide evidence that the oncogenetic lineage of PEComa, as a distinct TSC2‐linked neoplasm, is similar to that of angiomyolipoma. Copyright

Overexpression of KIT (CD117) in Chromophobe Renal Cell Carcinoma and Renal Oncocytoma

KIT expression has not been studied substantially in renal tumors. We analyzed the immunohistochemical expression for KIT in 256 conventional renal cell carcinomas (RCCs), 29 chromophobe RCCs, 25 papillary RCCs, 6 collecting duct RCCs, 6 unclassified RCCs, 7 renal oncocytomas, 20 urothelial carcinomas, 7 nephroblastomas, and 23 angiomyolipomas. We found that 24 chromophobe RCCs (83%) and 5 renal oncocytomas (71%) revealed membranous immunoreactivity for KIT while none of the RCCs of other types expressed KIT immunohistochemically. Sporadic cases of urothelial carcinoma and nephroblastoma were focally positive for KIT. All angiomyolipomas were negative. Genomic DNA extracted from the chromophobe RCCs and renal oncocytomas was submitted for polymerase chain reaction and direct sequencing of the juxtamembrane (exons 9 and 11) and tyrosine kinase (exons 13 and 17) domains. No mutation was found. Our results demonstrate that KIT could be a useful immunophenotypic marker for chromophobe RCC and renal oncocytoma; therefore, it has value for the precise classification of renal cortical epithelial tumors. However, the therapeutic relevance of KIT overexpression in these tumors is uncertain owing to the lack of mutations that would lead to constitutive activation of the protein.

Differential immunoprofiles of hepatocellular carcinoma, renal cell carcinoma, and adrenocortical carcinoma: a systemic immunohistochemical survey using tissue array technique.

The differential diagnoses of hepatocellular carcinoma (HCC), renal cell carcinoma (RCC), and adrenocortical carcinoma (ACC) are sometimes difficult due to their overlapping histologic features. Immunohistochemistry is a helpful adjunct in supporting the histologic diagnosis. In this study, the authors used the tissue array technique to systemically analyze the efficacy of different immunohistochemical panels in discerning these neoplasms. Immunohistochemical stains were performed on a total of 895 tumors (including 170 HCCs, 176 RCCs, and 40 ACCs) using monoclonal antibodies against hepatocyte antigen (HPA), CD10, RCC marker, vimentin, α-inhibin, keratins (KL-1, CAM 5.2, 7, and 20), epithelial membrane antigen, and polyclonal antibodies against carcinoembryonic antigen (pCEA) and α-fetoprotein, and antibodies Melan-A (A103), MOC31, and BG8. HPA immunostain alone detected 85.9% of HCCs, and the addition of canalicular pattern of pCEA and CD10 immunostains raised the sensitivity to 94.7%. RCC marker was positive in 54.5% of RCCs but was negative in all non-RCC tumors. Using positive CD10 and negative HPA and pCEA together with RCC marker increased the sensitivity to 74.4%. Immunoreactivity for α-inhibin and A103 could be detected in 67.5% and 55% of ACCs, respectively. When the two antibodies were combined, 82.5% of ACCs were labeled. Proper selection of immunohistochemical stains aid in the differential diagnosis of the three neoplasms. Using the tissue array technique, the authors also showed an effective model for comprehensive antibody testing.

CIP2A is a predictor of poor prognosis in colon cancer.

PurposeThe cancerous inhibitor of protein phosphatase 2A (CIP2A) oncoprotein is overexpressed in colon cancer tissue compared to normal colon mucosa. We investigated the impact of CIP2A on colon cancer.MethodsA tissue microarray consisting of 167 colon cancer specimens was investigated. The association between CIP2A and clinicopathological parameters was analyzed using the χ2 test. Survival was analyzed using the Kaplan–Meier method. The impact of CIP2A on proliferation and drug resistance was evaluated using the 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide test. An anchorage-independent colony formation assay was also performed.ResultsCIP2A was an independent prognostic factor in colon cancer after controlling for other clinical confounding factors, such as stage and lymphovascular invasion, particularly in stages III and IV (hazard ratio = 2.974, P < 0.001). The knockdown of CIP2A reduced the proliferation and anchorage-independent colony formation of colon cancer cells. Knockdown of CIP2A decreased the resistance of the cells to 5-fluorouracil, oxaliplatin, and SN38 (an active metabolite of irinotecan). Treatment with 5-fluorouracil, oxaliplatin, and SN38 decreased CIP2A expression.ConclusionsCIP2A is a prognostic factor in colon cancer. The knockdown of CIP2A reduced proliferation and anchorage-independent colony formation and increased 5-fluorouracil, oxaliplatin, and SN38 efficacy in colon cancer cell lines.

Risk of oral nonmalignant lesions associated with human papillomavirus infection, betel quid chewing, and cigarette smoking in Taiwan: an integrated molecular and epidemiologic study.

CONTEXT In contrast to previous studies about the association of oral squamous cell carcinoma with human papillomavirus (HPV) 16/18, the associations between nonmalignant oral lesions (chronic inflammation, submucous fibrosis, leukoplakia, and squamous papilloma) and HPV are much less well understood. OBJECTIVE We conducted this study using an in situ polymerase chain reaction in situ hybridization assay, which is one of the most sensitive methods for in situ viral detection. Other known oral cancer risk factors, including betel quid chewing and cigarette smoking, were also analyzed. DESIGN Oral specimens from 23 patients with submucous fibrosis, 36 patients with leukoplakia, 22 patients with squamous papilloma, and 21 patients without significant lesions were analyzed for the presence of HPV DNA. Their betel quid chewing and cigarette smoking histories were reviewed. RESULTS HPV-16 and HPV-18 were frequently identified in all 3 oral lesions (61.5% and 42.1%), while HPV-6 and HPV-11 were seen only in squamous papilloma (21.1% and 5.0%). HPV-18, betel quid chewing, and smoking were significantly associated with leukoplakia and squamous papilloma, while only betel quid chewing and smoking were significantly associated with submucous fibrosis. Multivariate analysis showed that the betel quid chewing habit remained an independent factor for leukoplakia and squamous papilloma. CONCLUSIONS Our data indicated that betel quid chewing and smoking habits are 2 important risk factors for these nonmalignant or premalignant oral lesions, while for high-risk HPV, only HPV-18--not HPV-16--is a significant risk factor for leukoplakia and squamous papilloma.

Cytoplasmic immunoreactivity for thyroid transcription factor-1 in hepatocellular carcinoma: a comparative immunohistochemical analysis of four commercial antibodies using a tissue array technique.

To evaluate the consistency of cytoplasmic immunoreactivity in hepatocellular carcinoma (HCC), we performed immunohistochemical stains for 4 commercial anti-thyroid transcription factor (TTF)-1 antibodies (DAKO, Zymed, Novocastra, Santa Cruz Biotechnology [see text]) on 77 HCCs and 334 nonhepatic epithelial tumors. The HCC cases were submitted for hepatocvte antigen immunohistochemical stain. Heat-induced epitope retrieval (HIER) methods were used: with DAKO Target Retrieval Solution, the positive rates of cytoplasmic TTF-1 in HCC for DAKO, Zymed, Santa Cruz, and Novocastra antibodies were 58% (45), 14% (11), 6% (5), and 0% (0), respectively; with EDTA buffer, the positive rates increased to 70% (54), 40% (31), 69% (53), and 0% (0), respectively. Immunoreactivity for the DAKO anti-TTF-1 antibody generally correlated with that for hepatocyte antigen. Among nonhepatic tumors, 2 of 6 ovarian mucinous carcinomas and 2 of 11 pancreatic adenocarcinomas showed cytoplasmic reactivity for the DAKO antibody; 28 cases showed nonspecific cytoplasmic staining for the Santa Cruz antibody with EDTA HIER. Zymed and Novocastra antibodies did not produce cytoplasmic staining in nonhepatic tumors. Owing to the staining variation, we do not consider TTF-1 a reliable marker to distinguish HCC. In general, the Novocastra antibody with EDTA HIER is superior for its consistent nuclear positivity and absence of erratic cytoplasmic staining.

Her2 amplification distinguishes a subset of non-muscle-invasive bladder cancers with a high risk of progression

Background Several studies have employed immunohistochemistry to detect Her2/neu overexpression in urothelial carcinomas, yielding a tremendous range of positive expression rates. Few studies have examined Her2 status in non-muscle invasive bladder cancer (NMIBC) using fluorescence in situ hybridisation (FISH). Aim To evaluate Her2 amplification in NMIBC (Ta/T1), to correlate the findings with recurrence and progression, and compare the Her2 status between primary and progressive tumours. Methods FISH and immunohistochemistry for Her2/neu were performed on tissue arrays consisting of 36 papillary urothelial neoplasms of low malignant potential (PUNLMPs), 190 low grade urothelial carcinomas (LG-UCs) and 178 high grade urothelial carcinomas (HG-UCs). 32 cases with specimens of both primary and progressive tumours (from Ta/T1 to T2–4) were included for comparative analyses. Results 16 HG-UCs (9.0%) showed Her2 gene amplification while none of the PUNLMPs and LG-UCs showed this aberration. There was 100% concordance in the status of Her2 amplification between primary and progressive lesions. Immunohistochemistry and FISH results were in closest agreement when overexpression was defined as 50% of tumour cells showing immunoreactivity. The cumulative incidences of recurrence and progression in Her2-amplified HG-UC were significantly higher than in those without amplification. Conclusions A subset of high-grade NMIBCs contain Her2 amplification and are associated with markedly aggressive behaviour. Her2 diagnostics are valuable for distinguishing patients who require diligent surveillance and would potentially benefit from anti-Her2 therapies.

Changing patterns in the frequency of Hodgkin lymphoma subtypes and Epstein-Barr virus association in Taiwan.

Epstein–Barr virus (EBV) infection is a risk factor for Hodgkin lymphoma (HL). To test whether the frequency of HL subtypes and their association with EBV has shifted with rising socioeconomic status in Taiwan, we compared the pathological features and EBV status, detected by in situ hybridization, of HL diagnosed between 1996 and 2007 (99 cases) and 1982 and 1995 (74 cases). The male‐to‐female ratio was 121:52 (2.3:1) and the mean age at presentation was 41.5 years. The overall EBV positivity rate was 50% (86/173 cases). Comparing the distribution of HL cases diagnosed at two different time periods, we found an increased frequency of the nodular sclerosis (NS) subtype (53 vs 68%, P = 0.045), a decreased frequency of the mixed cellularity subtype (35 vs 13%, P < 0.001), a reduced male‐to‐female ratio (2.9:1 compared to 1.4:1) and mean age (42.4 vs 36.6 years) in the NS subtype, and a significant decrease in EBV positivity rates among the NS and lymphocyte‐depletion subtypes (61 vs 39%, P = 0.03). These data indicate shifts in the frequency of histological subtype and EBV association for HL in Taiwan over the last decade, with a trend closer to that seen in Western countries and Japan. (Cancer Sci 2008; 99: 345–349)

Detection of Epstein-Barr virus genome within thymic epithelial tumours in Taiwanese patients by nested PCR, PCR in situ hybridization, and RNA in situ hybridization

Epstein–Barr virus (EBV) is known to be associated with a variety of tumours, including Burkitts lymphoma, nasopharyngeal carcinoma, and some carcinomas of other organs with similar lymphoepithelioma‐like features. The association between EBV and thymic epithelial tumours is inconclusive, as reports in this regard are not entirely consistent and the methods employed are of different sensitivity and specificity. This study examined 78 thymomas and 21 thymic carcinomas in Taiwanese patients, to detect the viral genome at both DNA and RNA levels. The tissue blocks were first screened by nested polymerase chain reaction (PCR) targeting on the first tandem internal repeats. The positive cases were further submitted for viral localization by in situ PCR insitu hybridization (ISH) and Epstein–Barr‐encoded RNA‐1 (EBER‐1) ISH. None of the thymomas showed a detectable EBV genome. Eight thymic carcinomas were positive for EBV by nested PCR, of which six displayed nuclear signals within the tumour cells by in situ PCR ISH and/or RNA ISH, one displayed signals within the lymphocytes, and one showed no discernible in situ signals. Most of them exhibited a lymphoepithelioma‐like morphology. These results show that nested PCR is a sensitive method for screening the EBV genome in thymic epithelial tumours. In situ PCR ISH is reliable for localization of the virus, in addition to EBER‐1 RNA ISH. Thymomas are not related to EBV, even in this endemic area. Thymic carcinomas, especially the lymphoepithelioma‐like thymic carcinomas, are more often associated with the virus. Copyright