Diagnostic utility of PAX8, TTF-1 and napsin A for discriminating metastatic carcinoma from primary adenocarcinoma of the lung

Abstract

TTF-1 and napsin A are useful biomarkers for differentiating primary lung adenocarcinoma from metastatic tumors. Studies have shown, however, that TTF-1 and napsin A also can be expressed in extrapulmonary carcinomas, and that a small fraction of primary lung adenocarcinomas do not co-express these two markers. We attempted to determine whether a tissue-specific transcriptional factor, PAX8, can help determine primary sites of lung carcinomas. Immunohistochemical stains for PAX8, TTF-1 and napsin A were performed on 103 cases of metastatic lung carcinomas from a variety of origins and 120 cases of primary lung adenocarcinomas. Our data demonstrated that all 103 metastatic carcinomas were negative for napsin A, while 14 (13.6%; four thyroid, two endometrium, three colon, one prostate, one salivary adenoid cystic, two renal cell carcinomas, and one ovary) showed weak to strong TTF-1 nuclear staining in 5-60% of the tumor cells. All primary lung adenocarcinomas were negative for PAX8, whereas 46 (44.7%) metastatic carcinomas from the kidney (29/33), ovary (6/8), endometrium (5/5), endocervix (1/1), thyroid (4/5) and urinary tract (1/3) were positive for PAX8. Our data demonstrate that of combined use of PAX8, TTF-1 and napsin A is reliable to separate reliably lung primary from metastatic tumors.

Cytologic Features and Immunocytochemical Profiles of Malignant Effusions with Metastatic Papillary Thyroid Carcinoma: A Case Series from a Single Institution

“…On subsequent VATS exploration, there was tumor studding of the visceral and parietal pleural surfaces, consistent with metastatic PTC. Although Pax-8 positivity is also found in Müllerian and renal primaries, the co-expression of TTF-1 and/or thyroglobulin is helpful in appropriately defining a thyroid primary [9,10,11]. However, given the focal staining pattern of thyroglobulin in our review, in limited cell block material, we would recommend prioritizing Pax-8 and TTF-1 over thyroglobulin.…”

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

“…Some show no or rare expression in lung carcinomas, making them excellent markers in identifying metastatic carcinomas of the lung. For instance, GATA3 is a very specific marker for breast and urothelial carcinomas ( Figure 8, a); PAX8 is expressed mostly in renal cell carcinoma, thyroid carcinomas, and carcinoma of the Müllerian tract 123,129 ; special AT-rich sequence-binding protein 2 (SATB2) (Figure 8, b) is reported to be a sensitive and specific marker in colorectal carcinomas 130 ; and arginase-1 is a newly recognized specific marker for hepatocellular carcinoma. Identification of SCC as primary or secondary to the lung is still a diagnostic dilemma because SCC exhibits the same histocytologic features and a similar immunoprofile in various primary sites.…”

“…SPT24 shows greater sensitivity in detecting more pulmonary tumors of all histologic subtypes at the expense of its specificity, contributing to a few reported expressions of TTF1 in breast, colon, and gynecologic tumors and colon. [123][124][125][126][127][128][129][130][131][132] Thus, 8G7G3/1 might be a better choice to differentiate primary from metastatic carcinomas. In recent years, many organspecific markers have been established.…”

Thyroid transcription factor 1 expression in a case of renal collecting duct carcinoma—Reply

“…As a result, in a case like the one presented it would be very important to rule out a metastatic lung carcinoma. No other immunohistochemical results are presented by Del Sordo, et al, but we believe that a PAX-8 immunostain in particular would be very helpful in this setting since this marker is consistently positive in CDC (staining 100% of cases in our cohort) [3] and negative in lung carcinoma [4,5].…”