Nonpulmonary Adenocarcinomas Research Articles

The role of thyroid transcription factor-1 in differentiating lung adenocarcinomas from non-pulmonary adenocarcinoma effusions.

Effusions, characterized by abnormal fluid accumulations in body cavities, present difficulties in identifying the primary organs of metastatic tumors through cytopathologic investigation, particularly in cancer-related complications. This retrospective cross-sectional laboratory study aimed to investigate the role of thyroid transcription factor-1 (TTF-1) in distinguishing lung adenocarcinomas from non-pulmonary adenocarcinomas in effusions. The study was conducted at Almobarak Cytopathology Laboratory, a private cytopathology laboratory. H&E was used to confirm the histological diagnosis of 58 archived cell blocks. TTF-1 immunostaining patterns were then correlated with the histological diagnosis. Statistical analysis, including numerical and graphical data summaries, was conducted using the Chi-square test in SPSS 23. TTF-1 expression was observed in 20 (34.4%) cases, while 38 (65.5%) cases showed no TTF-1 reaction. Positive TTF-1 was found in pleural fluid in 61.1 % of lung adenocarcinomas, while negative TTF-1 was found in only 3.4%. TTF-1 was not detected in the majority of peritoneal fluid samples. There was a highly significant relationship between pleural fluid, TTF-1, and lung adenocarcinoma (p=0.000). The data provided further evidence that TTF-1 is a useful marker for distinguishing pulmonary adenocarcinomas from non-pulmonary adenocarcinoma tumors.

Cell transfer technique for constructing cytological microarrays for immunocytochemical analysis.

To evaluate the utility of a proposed cell transfer technique for constructing cytological smear microarrays and its potential applications in multiplex immunocytochemical (ICC) staining. Ninety-six cytology smears, including two pericardial effusions, 22 ascites and 72 pleural effusions, were transferred to a 33-plex cytological microarray. Paired staining of thyroid transcription factor-1 (TTF-1) and calretinin ICC was performed in duplicate slides. Most of the smeared cells selected for transfer could be removed from the original slides with a minimal loss of cells and with no change in morphological features or immunoreactivity. Comparison of the staining results with immunohistochemical staining results, clinical history and histopathological reports available for each patient revealed that TTF-1 was positive in 32/33 metastatic pulmonary adenocarcinomas (PACs), 1/15 non-pulmonary adenocarcinomas and 0/45 benign effusions. The ICC results for TTF-1 on a transferred cytological microarray revealed high (97%) sensitivity and high (96.7%) specificity for the detection of metastatic PAC. Cytology microarrays can be constructed by transferring cells from serous fluid cytological smears, and cells transferred to the microarray retain their morphological integrity and immunoreactivity. Researchers can use the technique for simultaneous immunostaining of multiple specimens in studies of neoplastic or non-neoplastic diseases when available tissue samples are limited.

Diagnostic value of thyroid transcription factor-1 for pleural or other serous metastases of pulmonary adenocarcinoma: a meta-analysis.

The role of thyroid transcription factor 1 (TTF-1) in the diagnosis of metastatic pulmonary adenocarcinomas in pleural, pericardial, and peritoneal effusions has not been defined. This study aimed to assess the overall diagnostic accuracy of TTF-1 for metastatic pulmonary adenocarcinomas in pleural or other effusions. Literature search was conducted in PubMed, EMBASE, and other databases to find eligible publications. Quality was assessed according to standardized QUADAS-2 criteria. Sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and diagnostic odds ratio (DOR) were pooled. Summary receiver operating characteristic (SROC) curves were used to assess overall performance of the TTF-1 assay. A systematic search revealed 20 studies comprising a total of 1,213 subjects in this meta-analysis. The summary estimates were listed as follows: sensitivity, 0.74 (95% CI: 0.69–0.79); specificity, 0.99 (95% CI: 0.97–1.00); PLR, 78.16 (95% CI: 27.15–225.05); NLR, 0.26 (95% CI: 0.22–0.32); and diagnostic odds ratio, 297.75 (95% CI: 104.16–851.19). Estimated positive and negative post-probability values for metastatic pulmonary adenocarcinomas prevalence of 20% were 95% and 6%, respectively. The area under the SROC curve was 0.96. TTF-1 shows significant potential as a diagnostic marker to differentiate metastatic pulmonary from non-pulmonary adenocarcinomas in pleural or other effusions. These results justify larger, more rigorous studies to confirm such a diagnostic role.

Napsin A is a useful marker for metastatic adenocarcinomas of pulmonary origin

To address whether napsin A is useful for identifying metastatic adenocarcinomas of pulmonary origin. Fifty-four cases of adenocarcinoma that metastasized from the lungs to various sites and 1762 cases of carcinoma from various organs were immunostained for napsin A, TTF-1, CK7, CK20 and CDX2 using tissue microarray. The expression patterns of napsin A and TTF-1 in metastatic pulmonary adenocarcinomas were compared with matched primary lung tumours. Napsin A and TTF-1 were expressed in 87.0% and 81.5% of the metastatic pulmonary adenocarcinomas, respectively. Although there was no significant difference in the positivity of napsin A and TTF-1 as a single marker in metastatic pulmonary adenocarcinomas, the expression scores for napsin A were much higher than those for TTF-1 (P<0.001). Moreover, the positivity and expression scores of napsin A in primary pulmonary adenocarcinomas were maintained in metastatic adenocarcinomas better than TTF-1. Most non-pulmonary adenocarcinomas were negative for napsin A, except for renal cell carcinomas (13.4%), ovarian adenocarcinomas (7.1%) and uterine endometrial adenocarcinomas (14.5%). In particular, clear cell adenocarcinomas of ovary (68.8%) and uterus (66.7%) frequently expressed napsin A. These data suggest that napsin A may be a useful marker for identifying metastatic adenocarcinomas of pulmonary origin in combination with TTF-1.

Expression of Thyroid Transcription Factor-1 in Malignant Pleural Effusions

Separating adenocarcinoma of the lung from non-pulmonary adenocarcinoma or malignant mesothelioma is difficult, especially in cytology specimens. Consequently, it is important to identify markers that may facilitate this distinction. Thyroid transcription factor-1 (TTF-1) is a homeodomain containing transcription factor expressed selectively in the thyroid, lung, and diencephalon. TTF-1 is also expressed in adenocarcinomas of the lung and is widely used as a pulmonary adenocarcinoma marker in surgical specimens. However, the utility of TTF-1 has rarely been investigated in cytology. In this study, we evaluated the expression of TTF-1 in malignant pleural effusions. The primary tumors included 26 pulmonary adenocarcinomas, 26 non-pulmonary adenocarcinomas (13 breast, 5 ovarian, 2 gastric, 2 prostatic, 1 esophageal, 1 colonic, 1 pancreatic and 1 renal) and 4 malignant mesotheliomas. Immunocytochemistry was performed on sections of cell blocks, using a mouse monoclonal TTF-1 antibody (clone 8G7G3/1) and a biotin-streptavidin detection system. Nuclear immunoreactivity for TTF-1 was detected in 19 pulmonary adenocarcinomas. All non-pulmonary adenocarcinomas and malignant mesotheliomas were negative. These data indicate that TTF-1 maintains its sensitivity (73%) and specificity (100%) in cell block preparations and is useful in separating adenocarcinoma of the lung from non-pulmonary adenocarcinoma and malignant mesothelioma in cytology specimens.

Reliable Identification of Small Cell Lung Cancer in Cytological Specimens by Immunocytology

A reliable diagnosis of small cell lung cancers(SCLC) is of high clinical relevance. We investigatedwhether immunocytology substantially improves the diagnosticaccuracy of conventional cytology in diagnosingSCLC. Patients and Methods: 162 carcinomatous specimensclinically suspected to originate from pulmonaryneoplasms were investigated by cytology and immunocytology.Immunocytology was performed on smearsusing HEA125 and pancytokeratin antibodies as epithelialmarkers and MOC-1 as SCLC probe. Results: As histologicallyclarified, 114 specimens corresponded to pulmonaryneoplasms (SCLC = 51; non-small cell lung cancer:NSCLC = 59; mixed SCLC/NSCLC = 2; carcinoid = 2),48 to nonpulmonary adenocarcinomas. By conventionalcytology tumor cells were clearly detected in 93 (57.4%)and suspected in another 43 (26.5%) cases (83.9% overallsensitivity). Considering SCLC samples, tumor cells werediagnosed or suspected in 36 (70.5%), not identified in 10(19.6%), and misdiagnosed as hematological malignancyin 5 cases. Only 2 specimens were accurately diagnosedas SCLC. Using the epithelial antibodies all samples wereidentified as carcinomatous. MOC-1 stained all but oneSCLC, both SCLC/NSCLC, and both carcinoids. One SCLCbrush smear was MOC-1 negative, containing only squamousepithelium. 3 pulmonary adenocarcinomas stainedfalsely positive, all nonpulmonary carcinomas MOC-1 negative.Conclusion: Immunocytology substantially improvesthe diagnostic accuracy of cytology in diagnosingSCLC with a diagnostic sensitivity of 98% and specificityof 97%.

Role Of TTF-1, CK20, And CK7 Immunohistochemistry for Diagnosis of Primary and Secondary Lung Adenocarcinoma

Thyroid transcription factor-1 (TTF-1), and cytokeratin 7 (CK7) and cytokeratin 20 (CK20) have recently been reported to be useful to distinguish between primary and metastatic lung adenocarcinoma. The aim of this study was to determine the usefulness of the staining patterns of pulmonary adenocarcinoma with antibodies to TTF-1, CK7, and CK20 in differentiating primary from metastatic pulmonary adenocarcinoma. Of the 66 lung adenocarcinoma specimens that were enrolled in our study, there were 40 primary lung adenocarcinomas, 12 metastatic adenocarcinomas from breast, 13 metastatic adenocarcinomas from colon, and 1 metastatic adenocarcinoma from stomach. The expression of TTF-1, CK7, and CK20 was assessed by immunohistochemistry. We found that 73% of primary lung adenocarcinomas expressed TTF-1, whereas all nonpulmonary adenocarcinomas lacked TTF-1 staining. CK7 expression was significantly more frequent in adenocarcinomas of pulmonary and breast origin than gastrointestinal (GI) origin (p < 0.001). In contrast, CK20 expression was significantly more prevalent in adenocarcinoma that originated in the GI tract than that of pulmonary or breast origin (p < 0.001). A combination of TTF-1+CK7+CK20- was highly significantly associated with primary adenocarcinoma of lung (vs GI tract, p < 0.001; vs breast, p < 0.001). A combination of TTF-1-CKCK20+ was highly significantly associated with adenocarcinoma of GI origin (vs lung, p < 0.001; vs breast, p < 0.001). Our study has confirmed that expression of CK7, CK20, and TTF-1 is a useful immunohistochemical marker for diagnosis of lung tumors and for differential diagnosis of primary pulmonary adenocarcinomas from extrapulmonary adenocarcinomas metastatic to the lung. Application of this panel of antibodies might be expected to increase the accuracy of diagnosis.

D2-40 and podoplanin are highly specific and sensitive immunohistochemical markers of epithelioid malignant mesothelioma

Recent investigations have shown that podoplanin and the D2-40 monoclonal antibody, which reacts with an oncofetal antigen present in fetal germ cells, are highly reliable lymphatic endothelial markers. The observation that both of these markers are also expressed in normal and reactive mesothelial cells prompted an investigation into their potential value in the diagnosis of mesotheliomas. To determine whether podoplanin and D2-40 had any use in the diagnosis of these tumors, 40 mesotheliomas (29 epithelioid, 5 biphasic, and 6 sarcomatoid), 34 carcinomas of the lung (24 adenocarcinomas, 10 squamous carcinomas), 80 nonpulmonary adenocarcinomas (17 ovary, 10 breast, 10 colon, 10 kidney, 5 endometrium, 5 stomach, 5 pancreas, 5 prostate, 3 thyroid), 12 synovial sarcomas (6 biphasic and 6 monophasic), 5 angiosarcomas, and 2 adenomatoid tumors were immunostained with a monoclonal antibody to podoplanin and with the D2-40 antibody. Reactivity for both D2-40 and podoplanin was obtained in 25 (86%) of the 29 epithelioid mesotheliomas but in none of the carcinomas or sarcomatoid mesotheliomas. Positivity for D2-40 and podoplanin was also seen in the epithelioid components of 4 of 5 biphasic mesotheliomas and 4 of 6 synovial sarcomas, whereas the spindle cell components of these tumors were negative as were the monophasic synovial sarcomas. Two (40%) of the 5 angiosarcomas expressed these markers, thus confirming previous reports suggesting that some angiosarcomas may have lymphatic endothelial differentiation. Both of the adenomatoid tumors were also positive for D2-40 and podoplanin, a finding which provides further support for the mesothelial derivation of these tumors. It is concluded that, because of their high specificity and sensitivity for epithelioid mesotheliomas, D2-40 and podoplanin are very useful markers for the diagnosis of these tumors. When compared with the other markers that are currently available, in my opinion, they appear to be the best.

Cytology applications of p63 and TTF-1 immunostaining in differential diagnosis of lung cancers

The pathologic distinction of small cell from non-small cell-lung carcinoma is of considerable therapeutic significance. In particular, the ability to distinguish poorly differentiated non-small-cell lung cancer from small-cell lung carcinoma (SCLC) is at times difficult based upon morphology alone; available immunohistochemical markers such as neuroendocrine markers are of limited utility. We have demonstrated the role of p63 and thyroid transcription factor-1 (TTF-1) in the differential diagnosis of poorly differentiated squamous-cell carcinoma (PDSCC) versus SCLC, mostly in biopsy samples (Wu et al., American Journal of Clinical Pathology 2003;119:696-702). Here, we examine further the utility of this panel in cytologic cell-block samples of lung cancers including both primary and metastatic cancers of pulmonary origin, and cases of nonpulmonary cancers metastatic to lung in which differential diagnoses included a lung primary.Four-micron thick sections of 30 alcohol-fixed paraffin-embedded cell blocks from 14 lung FNAs, 6 liver FNAs, 3 bronchial washings, 1 subcarinal lymph node FNA, 1 iliac lymph node FNA, 1 pelvic mass FNA, 1 neck lymph node FNA, 1 adrenal FNA, and 1 pleural effusion were deparaffinized and stained with monoclonal antibodies reactive to p63 (1:800, Santa Cruz Biotechnology) and TTF-1 (1:50, Dako). Slides were stained for p63 using a streptavidin-biotin kit (BioGenex) and diaminobenzidine as chromagen, and counterstained with hematoxylin. Slides were stained for TTF-1 using a Dako Autostainer. Thirty cases were examined, including 8 primary SCLCs, 8 extra-pulmonary metastases of lung SCLCs, 4 PDSCCs and 4 primary pulmonary adenocarcinomas, and 6 nonpulmonary adenocarcinomas metastatic to lung or other sites. Fifteen out of 16 (94%) SCLC cases were p63-/TTF-1+, ranging in intensity from focal-weak to diffuse-strong; 1/16 SCLCs from a bronchial washing was p63-/TTF-1- but synaptophysin was positive. All 4 primary lung adenocarcinoma cases were p63-/TTF-1+; contrasting with nonpulmonary adenocarcinomas that were all p63-/TTF-1-. All 4 PDSCC cases were p63+/TTF-1-. The panel of p63 and TTF-1 appears to be useful in the diagnostic evaluation of cytologic cell-block samples of pulmonary malignancy.

Expression of TTF-1 and cytokeratins in primary and secondary epithelial lung tumours: correlation with histological type and grade.

To assess cytokeratin (CK) and thyroid transcription factor (TTF)-1 expression in primary epithelial lung tumours by comparison with non-pulmonary carcinomas and to correlate it with their histological type and grade. Immunohistochemistry using antibodies against CKs 5/6, 7, 19, 20 and TTF-1 was applied to 165 primary and 37 secondary epithelial lung tumours. CK5/6 is a sensitive and specific marker of lung squamous carcinomas being positive in 100% of cases. CK7 is a common marker of primary lung adenocarcinomas (100% of cases) but with a lower specificity since it is also observed in other primary lung carcinomas (70% of large-cell neuroendocrine carcinomas, 40% of large-cell carcinomas, 23% of squamous carcinomas) but also in 27% of non-pulmonary adenocarcinomas. Addition of an anti-CK20 may be useful to prove or disprove the pulmonary origin of an adenocarcinoma when there is a history of colon cancer. CK19 is ubiquitous but a predominant or exclusive 'dot-like' pattern is very suggestive of high-grade neuroendocrine carcinoma. TTF-1 is a very sensitive and specific marker to document the pulmonary origin of an adenocarcinoma if a thyroid origin is excluded. Its expression in neuroendocrine lung tumours depends on the tumour grade. Immunohistochemical expression of CKs and TTF-1 may be correlated with histological type and grade of lung primary epithelial tumours and may allow them to be distinguished from non-pulmonary carcinomas.

Thyroid transcription factor 1 in pulmonary adenocarcinoma

Aims: To discover whether variations in thyroid transcription factor 1 (TTF-1) staining in different subtypes and patterns of pulmonary adenocarcinoma are related to the putative origin of the tumour. In...

Value of Mesothelin Immunostaining in the Diagnosis of Mesothelioma

Mesothelin is a cell surface antigen of unknown function that is strongly expressed in mesothelial cells. Although it was reported in 1992 that immunostaining with the K1 anti-mesothelin antibody could be very useful in distinguishing between epithelioid mesotheliomas and pulmonary adenocarcinomas, no further studies have been published on the value of this marker in the diagnosis of mesotheliomas. To determine whether mesothelin can assist in discriminating epithelioid mesotheliomas from lung adenocarcinomas or from other carcinomas metastatic to the serosal membranes, 55 mesotheliomas (44 epithelioid, 3 biphasic, and 8 sarcomatoid), 48 carcinomas of the lung (31 adenocarcinomas, 17 squamous carcinomas), and 86 nonpulmonary adenocarcinomas (14 ovary, 5 peritoneum, 9 endometrium, 11 pancreas, 4 stomach, 16 colon, 12 breast, 9 kidney, 4 thyroid, and 2 prostate) were investigated for mesothelin expression using the recently available 5B2 anti-mesothelin monoclonal antibody. Reactivity was obtained in all 44 (100%) of the epithelioid mesotheliomas, 12 (39%) of the lung adenocarcinomas, and 42 (49%) of the nonpulmonary adenocarcinomas (14 [100%] ovary; 5 [100%] peritoneum; 6 [67%] endometrium; 10 [91%] pancreas; 2 [50%] stomach; 5 [31%] colon; and in none [0] of the breast, kidney, thyroid, or prostate). Three (18%) of the squamous carcinomas of the lung, but none of the sarcomatoid mesotheliomas, exhibited positivity for this marker, nor was any reactivity seen in the spindle cell component of the biphasic mesotheliomas. It is concluded that despite the low specificity of mesothelin for discriminating between epithelioid mesotheliomas and adenocarcinomas, immunostaining for this marker may have some utility in those instances in which the results obtained with the standard panel of immunohistochemical markers used for the diagnosis of mesotheliomas are equivocal. Because mesothelin is a highly sensitive positive marker for epithelioid mesotheliomas, a negative staining for this marker is an indication against such a diagnosis; however, because of its limited utility, it is not recommended for inclusion in the standard panel of immunohistochemical markers used in the distinction between mesotheliomas and adenocarcinomas.

Expression of Cytokeratin 5/6 in Epithelial Neoplasms: An Immunohistochemical Study of 509 Cases

Cytokeratin 5/6 (CK 5/6) immunoreactivity has been observed in the vast majority of cases of malignant mesothelioma but only rarely in pulmonary adenocarcinomas. Thus, CK 5/6 has been used to distinguish malignant mesothelioma from pulmonary adenocarcinoma. However, the utility of CK 5/6 in distinguishing pleural malignant mesothelioma from pleural metastases from nonpulmonary adenocarcinoma, as well as peritoneal malignant mesothelioma from peritoneal metastatic adenocarcinoma, has not yet been adequately addressed because the tissue expression of CK 5/6 in nonpulmonary neoplasms has not been well defined. We have studied the CK 5/6 expression in 509 cases of various epithelial tumors by immunohistochemistry. We found that the vast majority of cases of squamous cell carcinoma, basal cell carcinoma, thymoma, salivary gland tumor, and biphasic malignant mesothelioma were positive for CK 5/6. In addition, CK 5/6 immunoreactivity was detected in 15 of 24 cases (62%) of transitional cell carcinoma, in 5 of 10 cases (50%) of endometrial adenocarcinoma, in about one third of cases of pancreatic adenocarcinoma (38%) and breast adenocarcinoma (31%), and in one quarter of cases of ovarian adenocarcinomas (25%). Our study confirms the diagnostic utility of CK 5/6 immunohistochemistry in distinguishing biphasic mesothelioma from pulmonary adenocarcinoma but raises caution about its use for the differential diagnosis of pleural or peritoneal malignant mesothelioma versus pleural or peritoneal metastatic nonpulmonary adenocarcinoma, because many types of nonpulmonary adenocarcinomas may be positive for CK 5/6.

Value of Thyroid Transcription Factor-1, E-Cadherin, BG8, WT1, and CD44S Immunostaining in Distinguishing Epithelial Pleural Mesothelioma From Pulmonary and Nonpulmonary Adenocarcinoma

Value of Thyroid Transcription Factor-1, E-Cadherin, BG8, WT1, and CD44S Immunostaining in Distinguishing Epithelial Pleural Mesothelioma From Pulmonary and Nonpulmonary Adenocarcinoma

Value of thyroid transcription factor-1, E-cadherin, BG8, WT1, and CD44S immunostaining in distinguishing epithelial pleural mesothelioma from pulmonary and nonpulmonary adenocarcinoma.

The distinction between malignant pleural mesotheliomas and adenocarcinomas, particularly those originating in the lung, is a difficult diagnostic problem that can be facilitated by the use of immunohistochemical markers. In this study, the immunoreactivity of thyroid transcription factor-1 (TTF-1), E-cadherin, BG8, WT1, and CD44S was investigated in 50 epithelial mesotheliomas, and 40 pulmonary and 95 nonpulmonary adenocarcinomas. After analyzing the results, it was concluded that E-cadherin and BG8 are useful markers for distinguishing between epithelial mesotheliomas and adenocarcinomas of various origins, including the lung. Because TTF-1 expression is found almost exclusively in adenocarcinomas of the lung but is absent in mesotheliomas, immunostaining for this marker is particularly useful for distinguishing between these two malignancies. Although WT1 immunostaining may also be useful, its value, as determined in this study, is lower than that reported by other investigators. CD44S immunostaining does not have any practical value in discriminating between epithelial mesothelioma and lung adenocarcinoma.

Value of cytokeratin 5/6 immunostaining in distinguishing epithelial mesothelioma of the pleura from lung adenocarcinoma.

The immunohistochemical diagnosis of mesothelioma is commonly made by using a battery of antibodies that reacts with lung adenocarcinomas but not with epithelial mesotheliomas. Only recently have markers that are often expressed in mesotheliomas but not in adenocarcinomas been recognized. Some of these markers, however, require frozen tissue sections, whereas others are not commercially available, or their value remains controversial. In a recent publication, it was suggested that immunostaining for cytokeratin 5/6 could assist in distinguishing epithelial mesothelioma from lung adenocarcinoma. To determine the practical value of cytokeratin 5/6 immunostaining in the diagnosis of mesothelioma, 40 formalin-fixed, paraffin-embedded epithelial pleural mesotheliomas, 30 pulmonary adenocarcinomas, 93 nonpulmonary adenocarcinomas, 15 squamous carcinomas of the lung, 5 large cell undifferentiated carcinomas of the lung, and 12 metastatic transitional cell carcinomas to the lung were stained with the same antibody, which was obtained from a commercial source. Cytokeratin 5/6 reactivity was observed in all 40 mesotheliomas, but there was none in any of the 30 pulmonary adenocarcinomas. Focal or weak reactivity was observed in 14 of 93 nonpulmonary adenocarcinomas (10 of 30 ovarian, 2 of 10 endometrial, 1 of 18 breast, I of 7 thyroid, 0 of 10 kidney, 0 of 10 colonic, and 0 of 8 prostatic). All 15 squamous carcinomas of the lung, 6 of 12 transitional cell carcinomas metastatic to the lung, and 3 of 5 large cell undifferentiated carcinomas of the lung expressed cytokeratin 5/6. It is concluded that cytokeratin 5/6 immunostaining is not only useful in separating epithelial pleural mesotheliomas from pulmonary adenocarcinomas but also can assist in distinguishing epithelial mesotheliomas from nonpulmonary adenocarcinomas metastatic to the pleura.

Value of the MOC-31 monoclonal antibody in differentiating epithelial pleural mesothelioma from lung adenocarcinoma

MOC-31 is a monoclonal antibody that has recently become commercially available that recognizes an epithelial-associated, transmembrane glycoprotein often expressed in epithelial tumors. Although some authors have indicated that MOC-31 immunostaining can assist in distinguishing epithelial mesotheliomas from metastatic adenocarcinomas to the pleura, others have concluded that this marker has no value in separating these conditions. To determine whether MOC-31 immunostaining can assist in discriminating epithelial pleural mesothelioma from lung adenocarcinoma or from other carcinomas metastatic to the pleura, 38 epithelial pleural mesotheliomas, 40 pulmonary adenocarcinomas, 55 nonpuhnonary adenocarcinomas, six squamous cell carcinomas of the lung (SCCLs), three small-cell lung carcinomas (SCLCs), 19 bronchial carcinoids (BCs), and 15 transitional cell carcinomas (TCCs) were studied. Reactivity was obtained in two (5%) of the mesotheliomas, in all 40 (100%) pulmonary adenocarcinomas, in 45 (82%) nonpulmonary adenocarcinomas, in six (100%) SCCLs, three (100%) SCLCs, 15 (83%) BCs, and 10 (67%) TCCs. The staining in the two positive mesotheliomas was restricted to a few cells, in contrast to the pulmonary adenocarcinomas and most of the other carcinomas where it was often strong and diffuse. It is concluded that MOC-31 can be useful in separating epithelial pleural mesothelioma from pulmonary adenocarcinoma or from other epithelial malignancies involving the pleura.

Value of the Ber-EP4 antibody in differentiating epithelial pleural mesothelioma from adenocarcinoma. The M.D. Anderson experience and a critical review of the literature.

Although most studies have indicated that Ber-EP4 immunostaining can assist in differentiating epithelial pleural mesotheliomas from adenocarcinomas that metastasize to the pleura, the percentage of positive cases has varied greatly among different studies. Authors of a recent publication concluded that Ber-EP4 has no diagnostic utility in separating these conditions. To determine whether Ber-EP4 has any value in distinguishing mesothelioma from adenocarcinoma, 70 formalin-fixed epithelial pleural mesotheliomas, 20 pulmonary adenocarcinomas, 59 nonpulmonary adenocarcinomas, 4 squamous cell carcinomas of the lung, 6 transitional cell carcinomas, and 31 adenocarcinomas of unknown origin that metastasized to the pleura were stained with this antibody. Reactivity was observed in 18 (26%) of 70 mesotheliomas and in all 20 (100%) of the pulmonary adenocarcinomas, in 55 (93%) of the 59 nonpulmonary adenocarcinomas, in 4 (100%) of 4 squamous cell carcinomas of the lung, in 4 (67%) of 6 transitional cell carcinomas, and in 26 (84%) of 31 adenocarcinomas of unknown origin that metastasized to the pleura. The staining in the mesotheliomas was focal and restricted to a limited number of cells, in contrast with staining in the pulmonary adenocarcinomas in which it was invariably diffuse. The extent of the staining in the nonpulmonary adenocarcinomas and the metastatic adenocarcinomas of unknown origin was less consistent--negative or focal in some cases and diffuse in others. Therefore, while Ber-EP4 seems to be helpful in separating epithelial pleural mesotheliomas from lung adenocarcinomas, its value in distinguishing mesotheliomas from other tumors metastatic to the pleura is more limited and depends largely on the site of origin of the metastatic tumor.

Morphologic and immunocytochemical studies of bronchioloalveolar carcinoma at Duke university medical Center, 1968–1986 : Elson CE, Moore SP, Johnston WW. Department of Pathology, Box 3712, Duke University Medical Center, Durham, NC 27710. Anal. Quant Cytol Histol 1989;11:261–274

Between 1968 and 1986, the tumor registries at Duke University Medical Center and Durham VA Medical Center accumulated a total of 193 patients with a diagnosis of bronchioloalveolar carcinoma (BAC). All available histologic sections of primary lung tumors and all available respiratory and pleural cytologic material were reviewed for 135 cases having an initial histologic diagnosis of BAC and no history of a primary nonpulmonary adenocarcinoma. Thirty-nine cases showed a pure BAC pattern in histologic sections; 76 showed a dominant BAC pattern with focal areas of fibrosis and acinar differentiation; 16 were carcinomas with a focal BAC pattern; and 4 were adenocarcinomas lacking a BAC pattern. Of the 115 cases with at least a dominant BAC pattern, 51 showed predominantly mucinous differentiation while 64 showed predominantly nonmucinous differentiation. Adequate cytologic material was available for review from 111 patients. For cases having at least a dominant BAC pattern, tumor cells were present in 77 of 172 adequate sputums (44.8%), 36 of 133 bronchoscopy specimens (27.1%), 15 of 18 needle aspirates (83.3%) and 14 of 15 pleural fluids (93.3%). Of all patients in this group, 60.2% had at least one specimen positive for malignancy. No cytologic features clearly distinguished adenocarcinomas having only focal bronchioloalveolar differentiation from those with a pure or dominant BAC pattern. A significant degree of overlap was observed in the cytologic features of mucinous and nonmucinous tumors. Histologic sections from 19 mucinous and 16 nonmucinous tumors were stained with monoclonal antibody B72.3: all showed some staining, with no significant difference in degree of staining between the two groups. This suggests that expression of the tumor-associated glycoprotein TAG-72 is independent of mucinous differentiation.