Utility of WT-1, p63, MOC31, mesothelin, and cytokeratin (K903 and CK5/6) immunostains in differentiating adenocarcinoma, squamous cell carcinoma, and malignant mesothelioma in effusions

Uterine mesothelial cysts mimicking ovarian cysts in a primipara patient with a history of Cesarean section: A case report and review of the literature

OBJECTIVE

We describe a rare case of uterine mesothelial cysts mimicking ovarian cysts in a primipara patient with a history of Cesarean section.

CASE REPORT

A 39-year-old female patient with history of Cesarean section presented with dysmenorrhea. Sonography revealed that a hypoechoic and anechoic multicystic complex, which was located on the right side of the pelvic cavity, had infiltrated the adjacent posterior wall of the uterus, and it was preoperatively misdiagnosed as ovarian cysts with suspected endometrioma. Laparoscopic surgery revealed multiple cystic lesions filled with clear yellow fluid on the posterior uterine wall instead of the adnexa. Laparoscopic uterine cystectomy was performed, and the patient's recovery was uneventful. Pathohistological and immunohistochemical examinations confirmed the diagnosis of uterine mesothelial cysts.

CONCLUSION

Uterine mesothelial cysts should be considered in the differential diagnosis of pelvic lesions. Increasing the awareness of this rare disease can contribute to improved evaluation, decision-making, and disease management.

Mesothelin Expression in Human Tumors: A Tissue Microarray Study on 12,679 Tumors

Mesothelin (MSLN) represents an attractive molecule for targeted cancer therapies. To identify tumors that might benefit from such therapies, tissue microarrays including 15,050 tumors from 122 different tumor types and 76 healthy organs were analyzed for MSLN expression by immunohistochemistry. Sixty-six (54%) tumor types showed at least occasional weak staining, including 50 (41%) tumor types with at least one strongly positive sample. Highest prevalence of MSLN positivity had ovarian carcinomas (serous 97%, clear cell 83%, endometrioid 77%, mucinous 71%, carcinosarcoma 65%), pancreatic adenocarcinoma (ductal 75%, ampullary 81%), endometrial carcinomas (clear cell 71%, serous 57%, carcinosarcoma 50%, endometrioid 45%), malignant mesothelioma (69%), and adenocarcinoma of the lung (55%). MSLN was rare in cancers of the breast (7% of 1138), kidney (7% of 807), thyroid gland (1% of 638), soft tissues (0.3% of 931), and prostate (0 of 481). High expression was linked to advanced pathological tumor (pT) stage (p < 0.0001) and metastasis (p < 0.0001) in 1619 colorectal adenocarcinomas, but unrelated to parameters of malignancy in 1072 breast-, 386 ovarian-, 174 lung-, 757 kidney-, 171 endometrial-, 373 gastric-, and 925 bladder carcinomas. In summary, numerous important cancer types with high-level MSLN expression might benefit from future anti-MSLN therapies, but MSLN’s prognostic relevance appears to be limited.

Immunochemistry in the work-up of mesothelioma and its differential diagnosis and mimickers

The differential diagnosis in cellular effusions with cytological atypia often includes malignant mesothelioma (MM), reactive mesothelial proliferation, and malignancies of metastatic origin, particularly carcinomas. The International Reporting System for Serous Fluid recently established guidelines for reporting MM. In conjunction with the cytomorphologic evaluation, the role of immunochemistry (IC) was emphasized as a very useful tool in the workup of serous fluids, especially with the availability of novel markers. Utilizing a panel of markers, IC allows the characterization of the cells, whether mesothelial or not, and when mesothelial origin is established, IC can frequently assist in delineating its benign or malignant nature. IC can also confirm metastatic disease, allowing the identification of the primary origin in most cases. This review summarizes the current status of IC and its role in the diagnosis of MM and its differential diagnosis in serous fluids.

Greater specificity of p40 compared with p63 in distinguishing squamous cell carcinoma from adenocarcinoma in effusion cellblocks

Objective

Squamous cell carcinoma (SCC) rarely causes malignant effusions. Distinguishing between SCC and adenocarcinoma in effusion cytology can be a challenge. p63 and p40 have been frequently used to support squamous cell differentiation in both histological and cytological specimens. However, similar results in cytological preparations of effusion fluids have been rarely reported. This study was designed to assess the diagnostic value of p63 and p40 immunoreactivity for the differentiation of SCC from adenocarcinoma in malignant effusions.

Materials and Methods

Immunocytochemical staining of p63 and p40 was performed on thirty cellblock specimens, including ten malignant effusions carrying SCC and twenty malignant effusions showing adenocarcinoma. Any degree of nuclear staining was considered positive.

Results

Of the ten SCC cases, 100% tested positive for both p63 and p40, and most cases showed diffuse staining (>25% of tumor cells). The expression of p63 and p40 was detected in 4 (20%) and 2 (10%) of twenty adenocarcinoma cases, and the extent of staining was all focal (≤25% of tumor cells). The p63 reactivity showed 100% sensitivity, 80% specificity, 71% positive predictive value, and 100% negative predictive value for the differentiation of SCC from adenocarcinoma in malignant effusions. The sensitivity of p40 for SCC was 100%, the specificity was 90%, the positive predictive value was 83%, and the negative predictive value was 100%.

Conclusion

Although p63 and p40 are both useful markers for the diagnosis of SCC in malignant effusions, p40 is more specific than p63 in distinguishing SCC from adenocarcinoma.

Application of immunohistochemistry in diagnosis and management of malignant mesothelioma

Immunohistochemistry plays an indispensable role in accurate diagnosis of malignant mesothelioma, particularly in morphologically challenging cases and in biopsy and cytology specimens, where tumor architecture is difficult or impossible to evaluate. Application of a targeted panel of mesothelial- and epithelial-specific markers permits correct identification of tumor lineage in the vast majority of cases. An immunopanel including two mesothelial markers (calretinin, CK5/6, WT-1, or D2-40) and two epithelial markers (MOC-31 and claudin-4) offers good sensitivity and specificity, with adjustments as appropriate for the differential diagnosis. Once mesothelial lineage is established, malignancy-specific studies can help verify a diagnosis of malignant mesothelioma. BAP1 loss, CDKN2A homozygous deletion, and MTAP loss are highly specific markers of malignancy in a mesothelial lesion, and they attain acceptable diagnostic sensitivity when applied as a diagnostic panel. Novel markers of malignancy, such as 5-hmC loss and increased EZH2 expression, are promising, but have not yet achieved widespread clinical adoption. Some diagnostic markers also have prognostic significance, and PD-L1 immunohistochemistry may predict tumor response to immunotherapy. Application and interpretation of these immnuomarkers should always be guided by clinical history, radiographic findings, and above all histomorphology.

Anti-EpCAM antibodies for detection of metastatic carcinoma in effusions and peritoneal wash

Epithelial cell adhesion molecule (EpCAM) has been used as diagnostic/prognostic marker and therapeutic target. The aim of the present study was to compare immunoreactivity of antibodies against distinct epitopes in the ectodomain of EpCAM for detection of carcinoma from different primary sites and of different histological types in effusions and peritoneal wash. Two antibodies against epitopes in the EGF-like domain I (clones Moc-31 and Ber-EP4) and one antibody against the epitope in the cysteine-poor region (158210) of EpCAM were used (all commercially available). Independently of the clone used, EpCAM overexpression was observed in almost all samples when all the adenocarcinoma samples were analyzed together. By using Moc-31, EpCAM overexpression was observed in all samples of adenocarcinoma. Absence of EpCAM overexpression was observed in a few adenocarcinoma samples at some sites of tumor origin, including ovary, breast and stomach, when Ber-EP4 and 158210 were used. Regarding carcinomas aside from adenocarcinomas, histological types, such as squamous cell, urothelial and small cell carcinoma showed different degrees of EpCAM expression according to the antibody used. In squamous cell carcinoma, overexpression was observed only with the clone 158210. It was concluded that, overall, most samples of metastatic carcinoma from effusions showed overexpression of EpCAM. However, there are significant variations in its detection according to the primary site, histological type of the carcinoma and depending on the antibody used. Thus, the use of more than one type of anti-EpCAM antibody would increase the chance of its detection in metastatic carcinoma effusion.

Comparative Analysis of Immunohistochemical Markers for Differential Diagnosis of Hepatocelluar Carcinoma and Cholangiocarcinoma

Aims and background

Differential diagnosis of hepatocellular carcinoma and intrahepatic cholangiocarcinoma is sometimes difficult to accurately perform.

Methods

Eight markers including cytokeratin 7 (CK7), cytokeratin 19 (CK19), MOC31, CD10, glypican 3 (GPC3), claudin 4, biglycan and high mobility group A1 (HMGA1) were immunohistochemically stained in samples from 179 surgically resected hepatocellular carcinomas and 127 intrahepatic cholangiocarcinomas, and the rates of marker expression were statistically compared.

Results

With the exception of biglycan, 7 of the 8 markers were found to have significantly different expression patterns when comparing the two types of cancer (P <0.05). In intrahepatic cholangiocarcinomas, the expression rates of CK7, CK19, MOC31, claudin 4 and HMGA1 were 83.4%, 89.0%, 88.2%, 69.2%, and 31.5%, respectively. These rates of expression in intrahepatic cholangiocarcinomas were all higher than in those in hepatocellular carcinomas (CK7, 31.3%; CK19, 10.1%; MOC31, 34.0%; claudin 4, 11.2%; and HMGA1, 19.5%). The expression rates of GPC3, CD10, and biglycan were 72.6%, 39.7% and 10.0%, respectively, in hepatocellular carcinoma. These were higher than the rates found in intrahepatic cholangiocarcinomas (GPC3, 7.0%; CD10, 18.1%; and biglycan, 7.0%). In a multivariate logistic regression analysis, GPC3, CK19, MOC31 and claudin 4 were found to be independent markers for differentially diagnosing intrahepatic cholangiocarcinoma.

Conclusions

Based on our results, GPC3 and CK19 can be used as first-line markers for differential diagnoses of hepatocellular carcinoma and intrahepatic cholangiocarcinoma (accuracy rate, 73.5%), and additional combined screening for claudin 4 and MOC31 markers in GPC3(-) and CK19(-) tumors might increase the accuracy rate for distinguishing hepatocellular carcinoma from intrahepatic cholangiocarcinoma to 88.5%.

Immunohistochemistry in Peritoneal Mesothelioma: A Single-Center Experience of 244 Cases

Context.—

Diagnosis of malignant mesothelioma is more common in the chest than it is in the abdomen. Most published immunohistochemistry data are more applicable to pleural than to peritoneal mesothelioma.

Objective.—

To clarify the practical utility of 17 immunohistochemistry markers in the differential diagnosis of peritoneal mesothelioma with an emphasis on stains for which there is either contradictory information or a paucity of literature.

Design.—

Consultation files of peritoneal mesothelioma diagnoses rendered from 1999 to 2014 were reviewed; 244 cases were identified. The results of immunohistochemistry markers performed were tabulated.

Results.—

Immunohistochemistry markers positive in peritoneal mesothelioma in order of sensitivity were calretinin (244 of 244; 100%), WT1 (205 of 218; 94%), CK5/6 (173 of 194; 89%), mesothelin (132 of 150; 88%), and D2-40 (78 of 97; 80%). Markers used to differentiate carcinoma from mesothelioma showed immunoreactivity in peritoneal mesothelioma: estrogen receptor (2 of 84; 2%), B72.3 (6 of 196; 3%), CK20 (5 of 116; 4%), CD15 (7 of 192; 4%), p63 (3 of 62; 5%), carcinoembryonic antigen (9 of 199; 5%), PAX8 (12 of 191; 6%), progesterone receptor (5 of 71; 7%), Ber-EP4 (17 of 209; 8%), and CD138 (9 of 91; 10%). BAP1 loss, increasingly used in the differential diagnosis of benign versus malignant mesothelial proliferation, occured in 55% (99 of 181) of peritoneal mesothelioma cases.

Conclusions.—

The results support the experience that there is no definitive marker to rule out malignant mesothelioma, including PAX8, estrogen receptor, progesterone receptor, and p63 immunoreactivity. The high rate of immunoreactivity for mesothelin may have a role as a predictive marker for immune targeting. BAP1 loss of 55% in this cohort of peritoneal mesothelioma confirms published observations, and BAP1 retention is seen in a significant proportion of neoplastic cases.

Utility of GATA-3 in the work-Up of breast adenocarcinoma and its differential diagnosis in serous effusions:: A Cell-Block Microarray Study

BACKGROUND

GATA-3 is a transcription factor involved in human tissue growth and differentiation. It is a potential marker for breast carcinoma origin in metastasis and predictive of good prognosis. We aim to evaluate the role of GATA3 in determining the breast origin of metastatic adenocarcinoma in malignant effusions using immunohistochemistry on cell-block microarray in comparison with ER and PR results.

METHODS

Cell blocks from 100 cases of malignant and reactive serous effusions with confirmed diagnosis were selected; 28 mammary carcinomas, 64 extra-mammary adenocarcinomas (gastrointestinal, pulmonary, gynecologic), and 8 reactive mesothelium proliferation as control. Immunohistochemistry on cell-block microarray was used. Microarray slides were stained for GATA-3, ER and PR. Nuclear staining of >1% was considered positive.

RESULTS

GATA3, ER and PR were positive in 25 (89%), 20 (71%) and 16 (57%) of breast carcinoma cases, respectively. All non-breast cancer cases were negative for GATA-3 with the exception of one Müllerian adenocarcinoma (1.6%). The calculated sensitivity, specificity and positive predictive value (PPV) of GATA3 reactivity in determining the breast origin of metastatic adenocarcinoma was 89.3% (95% CI: 71.7-97.7%), 98.6% (95% CI: 91.6-99.9%) and 96.2% (95% CI: 80.4-99.9%), respectively. GATA3 positivity was associated with ER or PR positivity in 84% of cases.

CONCLUSIONS

GATA3 is a useful marker in determining the breast origin of metastatic adenocarcinoma in malignant serous effusions. Reactivity to GATA3 may indicate good prognosis. Diagn. Cytopathol. 2016;44:731-736. © 2016 Wiley Periodicals, Inc.

Establishment of anti-mesothelioma monoclonal antibodies

BACKGROUND

Mesotheliomas are aggressive, therapy-resistant tumors that are predicted to increase in incidence at least until 2020. The prognosis of patients with mesothelioma is generally poor because they are typically diagnosed at a late stage and their tumors are resistant to current conventional therapies. For these reasons, improved diagnosis and therapy are urgently required. To address these issues, the aim of our research was to develop novel mesothelioma-specific monoclonal antibodies (mAbs) as diagnostic and therapeutic agents.

METHODS

To develop anti-mesothelioma mAbs useful for diagnosis and therapy, we repeatedly immunized a BALB/c mouse with viable mesothelioma cells, alternating between those from three mesothelioma cell lines. We hybridized the spleen cells from this immunized mouse with P3U1 myeloma cells. We then screened supernatants harvested from the hybridoma clones by assessing whether they bound to a mesothelioma cell line not used for immunization and altered its morphology. We designed this developmental strategy to reduce the risk of obtaining clonotypic mAbs against a single mesothelioma cell line.

RESULTS

Our newly generated mouse anti-human mAbs immunostained clinical samples of mesotheliomas. One of the newly generated mAbs did not react with any other tumor cell line tested. Two other mAbs significantly inhibited the proliferation of mesothelioma cells.

CONCLUSION

These newly generated anti-mesothelioma mAbs are potentially useful as diagnostic and therapeutic agents for mesothelioma. Moreover, our novel strategy for establishing antitumor mAbs may facilitate the development of new diagnostic and therapeutic techniques for mesotheliomas and other malignancies.

The Use of Anti-Keratin 903 Antibodies to Visualize Colloid Bodies and Diagnose Lichen Planopilaris

Cytokeratins are a major component of colloid bodies that are essentially diagnostic of lichen planopilaris (LPP). Here, the authors assess the ability of the cytokeratin 903 antibody (CK-903) to stain colloid bodies and differentiate LPP from other histologically similar appearing primary cicatricial alopecias. A retrospective review of all specimens submitted to the dermatopathology department over a 2-year window identified 18 cases of LPP and 20 cases of histologically similar appearing entities (discoid lupus erythematosus or central centrifugal cicatricial alopecia) through a combination of H&E, elastic van gieson, and periodic acid-schiff stains. All 38 samples were then prospectively stained with CK-903. Colloid bodies were identifiable in 3 of the 18 LPP cases based on H&E alone but were seen in 9 of 18 cases when CK-903 was used. There were no cases where colloid bodies were seen on H&E but not subsequently identified with CK-903. Additionally, there was no CK-903 staining in any of the 20 cases of similar appearing entities except 1 case of discoid lupus erythematosus, which is known to occasionally show colloid bodies. The authors conclude that CK-903 is a useful adjunctive tool that will allow for a quicker, less costly, and more accurate diagnosis of LPP given its ability identify colloid bodies even in the setting of significant inflammation and fibrosis and its advantages over direct immunofluorescence of low cost, short preparation time, and lack of need for a specialized fluorescent microscope.

Expressions of Thyroid Transcription Factor-1, Napsin A, p40, p63, CK5/6 and Desmocollin-3 in Non-Small Cell Lung Cancer, as Revealed by Imprint Cytology Using a Malinol-Based Cell-Transfer Technique

BACKGROUND

The introduction of new therapies has made it important to differentiate between adenocarcinoma and squamous cell carcinoma. To allow the use of various immunocytochemical stains on limited materials, we tried transferring cells from a given smear to multiple slides. Using touch-preparation samples of 215 surgically resected non-small cell lung carcinomas of confirmed histologic classification (adenocarcinoma,n = 101; squamous cell carcinoma,n = 114), we performed immunocytochemistry for thyroid transcription factor-1, napsin A, p40, p63, CK5/6 and desmocollin-3, and compared cytologic staining results with the corresponding resection.

METHODS

We examined: (a) the expressions of the above 6 antibodies on cells transferred from touch imprints of resected specimens, the extent of staining being considered positive if more than 5% of the area was stained, and (b) the sensitivity, specificity, positive predictive value and negative predictive value for each antibody.

RESULTS

The histologic corresponding rate with Papanicolaou staining was only 73%. Regarding the differentiation of adenocarcinoma from squamous cell carcinoma, the sensitivity and specificity for napsin A in adenocarcinoma were 80 and 97%, respectively, while those for p40 in squamous cell carcinoma were 84 and 98%, respectively.

CONCLUSION

The immunocytochemical expressions of napsin A and p40 in imprint cytology seem to be of great utility for the accurate histological differentiation of lung cancers.

Efficacy and feasibility of the immunomagnetic separation based diagnosis for detecting sentinel lymph node metastasis from breast cancer

A purpose of this study was to establish a novel molecular diagnostic model and provide new insight into the intraoperative evaluation of the sentinel lymph node (SLN) metastasis in breast cancer. A total of 124 breast cancer patients who met the criteria of sentinel lymph node biopsy (SLNB) and underwent intraoperative biopsy were consecutively enrolled in this study. After the SLNs obtained from each patient were labeled, MOC-31 monoclonal antibody-mediated immunomagnetic separation (IMS) and flow cytometry were used to determine the expressions of breast cancer metastasis-related markers, including Mucin 1 (MUC1), CD44v6, and HER2. Alternatively, conventional intraoperative hematoxylin and eosin (HE) staining and cytokeratin immunohistochemistry (CK-IHC) were performed to detect potential SLN metastasis. The sensitivity, specificity, and false-negative rate of the three intraoperative diagnostic methods were compared and analyzed. A total of 55 positive-SLNs were found in 38 breast cancer patients using IMS, yielding a sensitivity of 86.4% (38/44), specificity of 94.7% (36/38), accuracy of 93.5% (116/124), false-positive rate of 2.5% (2/80), false-negative rate of 13.6% (6/44), positive predictive value of 95.5% (42/44), and negative predictive value of 93.0% (80/86). Patients with high expressions of CD44v6, MUC1, and HER2 in SLNs tended to have higher number of positive lymph nodes, among which the MUC1 and HER2 showed significant differences (P<0.05). Therefore, compared with conventional HE staining and CK-IHC, IMS technology has remarkably higher sensitivity and specificity and relative lower false-negative rate, thus making it an effective and feasible intraoperative detection method of SLN for breast cancer diagnosis to some extent.

Utility of GATA3, mammaglobin, GCDFP-15, and ER in the detection of intrathoracic metastatic breast carcinoma

INTRODUCTION

Breast carcinoma (BC) metastatic to the intrathoracic cavity is difficult to diagnose due to low sensitivity of current immunohistochemical (IHC) stains. Mammaglobin, gross cystic disease fluid protein-15 (GCDFP-15), and estrogen receptor (ER) immunomarkers show variable results. GATA3 is a recently described marker for detecting urothelial and breast cancers. Our goal is to test the utility of GATA3 in cell blocks from thoracic cytology specimens.

MATERIALS AND METHODS

We retrieved cases of BC that metastasized to the thoracic cavity from January 1, 2005 to September 30, 2013. IHC was performed on the cell blocks for the presence of GATA3, ER, GCDFP-15, and mammaglobin. Stains were scored quantitatively and qualitatively.

RESULTS

Fifty cases of metastatic BC found in pleural effusions and endobronchial ultrasound-guided fine-needle aspirates were identified in 48 patients. Thirty-four cases had sufficient material for IHC (19 pleural effusions, 15 endobronchial ultrasound-guided fine-needle aspirates). GATA3 showed strong nuclear positivity in 31 of 34 cases (91.2%). ER (25 of 34, 73.5%), mammaglobin (23 of 34, 67.6%) and GCDFP-15 (11 of 34, 32.6%) were positive in fewer cases. GATA3 and ER were concordant in 26 of 34 cases (76.5%) (24 ER/GATA3-positive, 2 ER/GATA3-negative). Discordant results were found in 8 of 34 cases (23.5%). Of these, GATA3 was positive and ER was negative in 7 cases. GATA3 was negative and ER was positive in 1 case.

CONCLUSIONS

GATA3 is more sensitive than ER, mammaglobin, or GCDFP-15 in detecting metastatic BC in cytologic specimens. GATA3 may be positive when ER is negative. In cytologic specimens with limited diagnostic material, GATA3 may be used as a first-line marker in a limited IHC panel to support metastatic BC.

Expression and diagnostic values of calretinin and CK5/6 in cholangiocarcinoma

BACKGROUND

Mesothelin, a mesothelial marker, has been found expressed in and as a potential treatment target of cholangioacarcinoma (CC). It is possible that CC may be derived from the cells sharing mesothelial markers. However, the expression of other mesothelial markers in CC is largely unknown.

METHODS

Thirty CC cases (10 extrahepatic and 20 intrahepatic) were retrieved from our institutional archive. The immunohistochemical study of Calretinin (DC8), WT1 (6F-H2), Lymphatic Endothelial Marker (D2-40), CK5/6 (D5/16 B4) and CK19 (b170) was done on formalin fixed paraffin embedded sections for 2-3 blocks of each case. We compared the expression levels between CC and normal bile duct (NBD) on the same block.

RESULTS

All of the CC and NBD are positive for CK19 (23/23) and negative for WT1 (0/23) and D2-40 (0/23), except one CC positive for D2-40(1/30, 3.3%) and one NBD positive for WT1 (1/23, 4.3%). Calretinin immunoreactivity was detected in 52.2% (12/23) of CC, but none in NBD (0/23). CK5/6 was also detectable in 73.3% (22/30) of CC and all NBD (30/30). Increased expression of calretinin and reduced expression of CK5/6 were more likely associated with CC than NBD (P < 0.001 and P = 0.002, respectively). The sequential staining pattern of positive calretinin and negative CK5/6 in calretinin negative cases has a sensitivity of 69.57% and a specificity of 100% for differentiating CC from NBD. CK5/6 expression was also more likely associated with well-differentiated CC (7/7 versus 12/20 in moderately differentiated, and 9/10 in poorly differentiated, P = 0.019) and extrahepatic CC (10/10 versus 12/20 in intrahepatic, P = 0.029), but there was no association between the calretinin expression and the CC grade or location.

CONCLUSION

Calretinin and CK5/6 immunohistochemical stains may be useful for diagnosing a CC. Their immunohistochemical results should be interpreted with caution in the cases with differential diagnoses of mesothelioma and CC. A full mesothelioma panel, including WT1 and/or D2-40, is recommended to better define a mesothelial lineage. The biology of calretinin and CK5/6 expression in CC is unclear, but might shed light on identifying therapeutic targets for CC.

Claudin-4 immunohistochemistry is highly effective in distinguishing adenocarcinoma from malignant mesothelioma in effusion cytology

BACKGROUND

Adenocarcinoma can be challenging to distinguish from malignant mesothelioma in effusions, and this distinction often requires ancillary studies and clinical correlation. Immunohistochemistry for claudin-4, a tight-junction-associated protein, has recently been shown to distinguish adenocarcinoma from malignant mesothelioma, mostly in surgical specimens. Our aim was to validate and assess the immunoreactivity profile of claudin-4 in a large series of malignant effusions.

METHODS

We evaluated 159 malignant effusions (84 adenocarcinomas and 75 malignant mesotheliomas). Claudin-4 immunohistochemistry was performed on cell-block paraffin sections and scored for staining intensity, staining pattern (cytoplasmic versus membranous), and percentage of positive tumor cells. Appropriate positive and negative controls were used throughout.

RESULTS

All cases of mesothelioma were negative for claudin-4 (0 of 64). Eighty-three of 84 cases of adenocarcinoma were positive (99%); 1 case of serous carcinoma was negative. Most adenocarcinomas showed strong and diffuse membranous staining (71 of 84; 84%); 12 cases (14%) showed membranous staining of moderate intensity. The overall sensitivity for adenocarcinoma was 99% (83 of 84).

CONCLUSIONS

Claudin-4 immunohistochemistry effectively distinguishes adenocarcinoma from malignant mesothelioma with high sensitivity and specificity in the evaluation of malignant effusions.

Expression of Wilms' tumor gene (WT1) is associated with survival in malignant pleural mesothelioma

INTRODUCTION

Calretinin and Wilms' tumor gene (WT1) are mesothelial markers routinely used to confirm the diagnosis of malignant pleural mesothelioma (MPM). We investigated the prognostic value of calretinin and WT1 expression in predicting survival in a series of patients diagnosed with MPM in our institution.

MATERIALS AND METHODS

Fifty-two patients diagnosed of MPM were retrospectively reviewed. Calretinin and WT1 were stained for IHC analysis in formalin-fixed, paraffin-embedded sections and positivity was considered for tumors with >1 % of tumor cells stained. Survival data were calculated by the Kaplan-Meier method and Cox regression was used to evaluate the prognostic value of the variables.

RESULTS

Calretinin IHC expression was positive in 83.7 % of patients and WT1 in 78.1 %. A significant association of calretinin and WT1 expression with epithelial histology was detected (p = 0.030 and p = 0.010). We found a significant increase in OS in patients with epithelial subtype, PS1 and neutrophil-lymphocyte ratio (NLR) ≤5 (p < 0.05). In the IHC markers analysis, we found a significant increase in OS for patients with WT1 positive expression (16.4 vs. 2.3 m, p = 0.013), but not differences for calretinin expression (16.6 vs. 5.0 months, p = 0.37). In the multivariate analysis, epithelial histology and WT1 remained as significant prognostic factors for survival (p = 0.004 and p = 0.010, respectively).

CONCLUSION

In our series of 52 MPM patients, epithelial histology, PS, NLR and WT1 expression are significant prognostic factors for survival. We concluded that WT1, but not calretinin, is a useful prognostic factor in MPM. The role of WT1 assessment is worth of prospective validation in future studies on MPM.

Value of PAX8, PAX2, napsin A, carbonic anhydrase IX, and claudin-4 immunostaining in distinguishing pleural epithelioid mesothelioma from metastatic renal cell carcinoma

Both mesotheliomas and renal cell carcinomas can present a wide variety of cytomorphologic features and histologic patterns. Because of this, renal cell carcinomas metastatic to the pleura and lung can be confused with mesotheliomas. Recently, a variety of positive carcinoma markers, including kidney-associated markers, have become available. The aim of this study is to investigate the value of some of these markers, specifically PAX8, PAX2, napsin A, carbonic anhydrase IX, and claudin-4, for assisting in distinguishing pleural epithelioid mesotheliomas from metastatic renal cell carcinomas. To do so, a total of 40 pleural epithelioid mesotheliomas and 55 renal cell carcinomas (33 clear cell, 10 papillary, and 12 chromophobe) were investigated. In all, 91% of the renal cell carcinomas expressed claudin-4, 89% PAX8, 60% PAX2, 71% carbonic anhydrase IX, and 29% napsin A. All of the mesotheliomas were positive for carbonic anhydrase IX and were negative for all of the other markers. On the basis of these results, it is concluded that claudin-4 and PAX8 have a higher sensitivity and specificity for assisting in discriminating between pleural epithelioid mesotheliomas and renal cell carcinomas when compared with all of the other positive carcinoma markers that are, at present, recommended to be included in the immunohistochemical panels used in this differential diagnosis. Even though PAX2 and napsin A are highly specific, because of their low sensitivity, they have only a limited value. Carbonic anhydrase IX is not useful.

Primary intrahepatic malignant mesothelioma with multiple lymphadenopathies due to non-tuberculous mycobacteria: A case report and review of the literature

Primary intrahepatic malignant mesothelioma (PIHMM) is an extremely rare tumor with clinicopathological characteristics that remain to be elucidated. The current study presents the case of a 68-year-old female with PIHMM and multiple lymphadenopathies due to non-tuberculous mycobacteria. The patient presented with an intrahepatic tumor, 70 mm in diameter, in the right lobe of the liver. An ultrasound-guided fine-needle aspiration biopsy of the liver tumor revealed findings that were consistent with an intrahepatic malignant mesothelioma. The systemic lymph node swellings were due to epithelioid granulomas that were caused by non-tuberculous mycobacteria. However, a hepatic rupture occurred due to the rapid growth of the liver tumor and consequently, a surgical resection was not performed. A review of the literature revealed that the clinicopathological characteristics of PIHMM are similar to those of non-occupational mesothelioma. However, PIHMM is usually a solitary tumor and is rarely associated with cavity effusion in contrast with conventional mesothelioma. Therefore, surgical resection with curative intent is often recommended for patients with PIHMM.

Differential diagnosis of reactive mesothelial cells and malignant mesothelioma cells using the cell proliferation markers minichromosome maintenance protein 7, geminin, topoisomerase II alpha and Ki-67

OBJECTIVE

The aim of this study was to evaluate whether the immunocytochemical expression of cell proliferation markers, such as minichromosome maintenance protein 7 (MCM 7), geminin, topoisomerase II alpha (topo IIα) and Ki-67, which are different types of cell proliferation markers, could be useful for their differential diagnosis in reactive mesothelial cells and malignant mesothelioma cells obtained from body cavity fluids.

STUDY DESIGN

Samples diagnosed and later histologically confirmed as reactive mesothelial cells (39 cases) or malignant mesothelioma (32 cases) in body cavity fluids were examined. Immunocytochemical staining of MCM 7, geminin, topo IIα and Ki-67 was performed with the immunoperoxidase polymer method.

RESULTS

Labeling indices (LIs) of MCM 7 (cutoff value 20.0%; sensitivity 100%; specificity 100%), geminin (cutoff value 4.5%; sensitivity 88.0%; specificity 70.0%), topo IIα (cutoff value 11.0%; sensitivity 88.0%; specificity 92.0%) and Ki-67 (cutoff value 15.3%; sensitivity 78.0%; specificity 79.0%) of malignant mesothelioma cells were significantly higher than those of reactive mesothelial cells.

CONCLUSION

LIs of MCM 7, geminin and topo IIα can be reliable tools for the differential diagnosis of reactive mesothelial cells and malignant mesothelioma cells.

Best immunohistochemical panel in distinguishing adenocarcinoma from squamous cell carcinoma of lung: tissue microarray assay in resected lung cancer specimens

The emergence of the targeted therapies for non-small cell lung carcinoma (NSCLC) has generated a need for accurate histologic subtyping of NSCLC. In this study, we assessed the utility of immunohistochemical markers that could be helpful in distinction between adenocarcinoma (ADC) and squamous cell carcinoma (SCC). We performed a battery of immunohistochemistry using tissue microarray for napsin-A, Thyroid transcription factor 1 (TTF-1), p63, cytokeratin (CK) 5/6, thrombomodulin (CD141), Epithelial-related antigen (MOC-31), carcinoembryonic antigen (CEA), Cyclooxygenase 2 (COX-2), high-molecular-weight CK (HMWCK), p27kip1 (p27), and Rb protein in 129 resected primary NSCLC with 81 ADCs and 48 SCCs and 10 metastatic ADC to the lung (primary in colon, 7 cases; stomach, 2 cases; vagina, 1 case). Cases of ADC and SCC were morphologically unequivocal and solid tumors with no definite squamous or glandular differentiation were excluded for this analysis. Napsin-A and TTF-1 were positive in 81% and 70% of ADC and in 0% and 2% of SCC, respectively, whereas P63 and CK5/6 were positive in 91% and 90% of SCC and in 9% and 4% of ADC, respectively (P < .001). CD141 stained significantly higher in SCC over ADC (positive in 2% of ADC and 46% of SCC. MOC-31, CEA, COX-2, HMWCK, p27, and Rb appeared to be not useful markers in distinction between ADC and SCC because of their low specificity. None of metastatic ADC to the lung showed positive for napsin-A and TTF-1. It was evident that combination of napsin-A, TTF-1, CK5/6, and p63 was the best immunohistochemical panel in differentiating ADC from SCC of the lung in this study. CD141 appeared to be a potential new marker for SCC with high specificity. Cyclooxygenase 2, MOC-31, CEA, HMWCK, p27, and Rb showed less specificity for differentiation ADC from SCC.

Application of immunohistochemistry in the diagnosis of epithelioid mesothelioma: a review and update

A large number of immunohistochemical markers that can assist in the differential diagnosis of epithelioid mesotheliomas are currently available. Because these markers are expressed differently in the various types of carcinomas that can metastasize to the serosal membranes and can potentially be confused with epithelioid mesothelioma, their selection for inclusion in a diagnostic panel largely depends on the differential diagnosis, as well as on which ones work the best in a given laboratory. Traditionally, the panels used in the differential diagnosis of epithelioid mesothelioma have consisted of a combination of positive mesothelioma markers and broad-spectrum carcinoma markers. At present, a wide variety of organ-associated carcinoma markers such as thyroid transcription factor-1 and napsin A for the lung, PAX 8 and PAX 2 for the kidney, and Müllerian-derived tumors; gross cystic disease fluid protein-15 and mammaglobin for the breast; and CDX2 for intestinal differentiation are available, which can assist in establishing the site of origin of an adenocarcinoma when included in a diagnostic panel. This article provides updated information on the composition of the panels of markers recommended in the various differential diagnoses.

Tissue-sparing application of the newly proposed IASLC/ATS/ERS classification of adenocarcinoma of the lung shows practical diagnostic and prognostic impact

The histologic subtype of non-small cell lung cancer (NSCLC) determines treatment strategies and the need for genetic analyses. Since most NSCLC are diagnosed on small biopsy or cytologic specimens, an accurate but tissue-sparing approach is necessary. To date, consensus for a general diagnostic algorithm is lacking. To test the diagnostic and clinical relevance of the recently published multidisciplinary guidelines by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society, we examined 371 surgically resected NSCLCs brought into tissue microarray format. The antibody panel thyroid transcription factor-1 (TTF-1), p63, cytokeratin (CK)5/6, and CK7 is diagnostic for most cases (>94%). Faint/focal staining for CK7 is negligible for classificatory purposes. Grading adenocarcinomas according to histologic architecture is prognostically significant (median overall survival for well/moderate differentiation, 72.5 months; for poor differentiation, 38.5 months; P = .019). Double stains combining the aforementioned nuclear and membranous markers are highly diagnostic for NSCLC, conserving tumor tissue for subsequent analyses.

Pathological and molecular biological approaches to early mesothelioma

Malignant mesothelioma is an asbestos-related malignancy that arises primarily from mesothelial cells on the serosal surfaces of the pleural, peritoneal, and pericardial cavities. Malignant pleural mesothelioma (MPM) is most common, and its incidence is dramatically increasing worldwide as a result of widespread use of asbestos. Morphological discrimination between MPM and reactive mesothelial hyperplasia is difficult, and the most reliable pathological criterion for malignancy is mesothelial proliferation invading deeply into subpleural adipose tissues. To establish radical cure of MPM, it is crucial to find early-stage MPM of epithelial type, in which mesothelial proliferation is localized on the serosal surface of parietal pleura or limited within the submesothelial fibrous tissues of parietal pleura. The initial clinical presentation for patients with MPM is frequently dyspnea and/or chest pain due to large pleural effusion, and cytological analysis of pleural effusions is valuable to find patients with early-stage MPM of epithelial type. Recently, cytological features of MPM in pleural effusion, molecular markers for MPM, and genetic alternations of MPM have been reported. In this review, we discuss major issues on pathological and molecular biological approaches for diagnosis of early-stage MPM of epithelial type.

Advances in the diagnosis of pleural disease in lung cancer

Pleural disease in lung cancer can be benign or malignant with the latter carrying a grave prognosis. In this review, we describe and discuss the advances in pleural imaging, procedures, and biomarkers for the diagnosis of pleural diseases in lung cancer. Ultrasound and computed tomography are increasingly applied in the planning of pleural procedures to enhance diagnostic accuracy and safety whilst pleuroscopy gives excellent yield in excess of 93% in the evaluation of cytology negative pleural effusions. Invasion beyond the elastic layer of the visceral pleura upstages lung cancer, and may indicate a need for adjuvant chemotherapy. Biomarkers isolated from pleural fluid or tissue may aid in diagnosis and guide treatment in the future. Magnetic resonance imaging, positron emission tomography, narrow band imaging of the pleura and autofluorescence thoracoscopy are technologies that require further evaluation to better define their respective roles in the diagnostic algorithms of pleural diseases in lung cancer.

Immunocytochemistry of CD146 is useful to discriminate between malignant pleural mesothelioma and reactive mesothelium

Malignant pleural mesothelioma is a refractory tumor with poor prognosis associated with asbestos exposure. Pleural effusion is frequently observed in patients with malignant pleural mesothelioma, and cytological analysis is effective to detect malignant pleural mesothelioma. However, cytological discrimination between malignant pleural mesothelioma and reactive mesothelium is often difficult. Increased expression of CD146, a cell adhesion molecule, has been reported to be closely associated with an advanced stage of malignant melanoma, prostate cancer, and ovarian cancer. In this study, to evaluate the diagnostic utility of CD146 for discrimination between malignant pleural mesothelioma and reactive mesothelium, we examined immunocytochemical expression of CD146 in malignant pleural mesothelioma and reactive mesothelium using two clones of CD146 antibody, OJ79 and EPR3208, on smear specimens of effusion fluids. Immunocytochemical stains were semiquantitatively scored on the basis of immunostaining intensity (0, negative; 1, weak positive; 2, moderate positive; and 3, strong positive). CD146 expression was detected in 15 of 16 malignant pleural mesothelioma with median immunostaining score of 3 by OJ79, and in 19 of 21 malignant pleural mesothelioma with median immunostaining score of 2 by EPR3208. Strong immunoreactivity of CD146 was observed at the apposing surfaces of cell-cell interactions on the plasma membrane of mesothelioma cells. In addition, one OJ79-negative case of malignant pleural mesothelioma was positive for CD146 by EPR3208 and two EPR3208-negative cases of malignant pleural mesothelioma were CD146 positive by OJ79, showing that all 23 malignant pleural mesothelioma cases were positive for CD146 by either OJ79 or EPR3208. On the other hand, CD146 expression was undetectable in all reactive mesothelium cases by OJ79 and EPR3208. The sensitivity of OJ79 and EPR3208 was 94 and 90%, respectively, and the specificity was 100% for both clones. We propose that CD146 is a sensitive and specific immunocytochemical marker enabling differential diagnosis of malignant pleural mesothelioma from reactive mesothelium.

Dual use of a single Wilms' tumor 1 immunohistochemistry in evaluation of ovarian tumors: a preliminary study of 20 cases

Our previous studies revealed that a single Wilms' tumor 1 (WT-1) immunohistochemistry can be used to elucidate both the myoepithelial cells and blood vessels of human breast tumors. As the human ovary is rich in blood vessels, and WT-1 has been used as a biomarker for ovarian tumors, our current study attempted to assess if a single WT-1 immunohistochemistry has dual usages in evaluation of ovarian tumor and endothelial cells. Paraffin-embedded tissue sections were prepared from 20 cases of ovarian tumors. A set of four consecutive sections from each case were subjected to immunohistochemistry with a mouse monoclonal antibody against the human WT-1 protein, a well defined ovarian tumor marker, CA-125, and a endothelial cell phenotypic marker, CD34, respectively. From each case, 4-5 randomly selected fields were photographed, and expression of these molecules in the same structures were compared. Distinct WT-1 immunoreactivities were seen in both ovarian tumor and endothelial cells. Over 90% of WT-1 positive tumor and endothelial cells were positive for CA-125 and CD34, respectively. Similarly, over 90% of CA-125 or CD34 positive cells co-express WT-1 in tumor or endothelial cells, respectively. Our findings suggest that a single WT-1 immunohistochemistry can be used to assess both the tumor cells and micro-vascular density in ovarian tumors. Our findings also suggest that as WT-1 is expressed in both tumor and endothelial cells, the development of therapeutic agents to target WT-1 may provide an effective treatment option for ovarian cancer.

Benign and Malignant Mesothelial Proliferation

Malignant mesothelioma (MM) is a rare primary malignant tumor of the surface serosal cells. The diagnosis of MM is challenging with a broad differential diagnosis. For many decades, studies have focused on distinguishing MM from other types of cancer; however, benign mesothelial cell hyperplasia, especially in small biopsies, has emerged as a major problem. The features of pleural lesions are somewhat different from peritoneal diseases, and this article primarily focuses on pleural diseases. Thorough interpretation and correlation of clinical, radiologic, and pathologic findings are essential for a correct diagnosis.

Scoring system for differential diagnosis of malignant mesothelioma and reactive mesothelial cells on cytology specimens

Cytology is the only useful tool in the detection of malignant mesothelioma (MM) at an early stage. No other methods, such as immunocytochemistry or electron microscopy, are available to distinguish MM from reactive mesothelial cells (RMC). Some objective analysis of cytology specimens is necessary. On the basis of our case review and cytological features described in previous articles, we developed a scoring system for malignant mesothelioma (SSMM) of effusion cytology to distinguish MM cells from RMC. Mesothelioma cells in effusions from 22 patients (20 pleural and 2 peritoneal mesotheliomas) were compared with RMC from 20 patients without obvious tumor cells and 50 effusions containing metastatic carcinoma cells. The SSMM is based on characteristic features of mesothelial and malignant cells. The total achievable score is 10 points: one point each is given for variety of cell size, cyanophilic cytoplasm with villosity/windows/bleb, sheet-like arrangement, mirror-ball-like cell clusters, nuclear atypia, and cannibalism, respectively. Further two points each are ascribed for acidophilic large nucleoli and multinucleated cells with more than eight nuclei. The total score for each of the 22 mesotheliomas was more than 5 points. On the other hand, all RMC and the 50 metastatic carcinoma cases scored less than 3 points, aside from two cases that were treated with OK432. No single characteristic feature was observed to be consistent within the 22 mesotheliomas analyzed. Ancillary use of immunocytochemistry, such as podoplanin (D2-40) and calretinin, supported the diagnostic accuracy of the SSMM. SSMM is useful for the differential diagnosis of MM.

Malignant pleural mesothelioma

Malignant pleural mesothelioma continues to be a challenge. The diagnosis and treatment of patients with malignant pleural mesothelioma requires a multidisciplinary approach. The diagnosis is best made by thoracoscopic biopsy and the aid of immunohistochemistry. Molecular studies identified inactivation of the neurofibromatosis-2 gene and INK4alpha/ARF to be key events in tumorigenesis. Based on the results of a Phase III trial, the combination of cisplatin with pemetrexed has become the preferred choice for chemotherapy, although there is suggestive evidence for the activity of other platin combinations based on Phase II studies. The optimal second-line chemotherapy remains to be defined. Surgical interventions ranging from pleurectomy/decortication to extrapleural pneumonectomy are increasingly offered in specialized centers, and the results of multimodality approaches with neoadjuvant or adjuvant chemotherapy and extrapleural pneumonectomy are encouraging. Ongoing investigations are defining the role of postoperative radiotherapy and the clinical activity of tyrosine kinase inhibitors targeting VEGFR2, histone deacetylase inhibitors and proteosome inhibitors.