A study of immunohistochemical differential expression in pulmonary and mammary carcinomas

Abstract

The risk of developing a second primary cancer is increased in patients with breast cancer, and the lung is one of the major sites involved. Moreover, the lung is the major metastatic site for breast cancers. A distinction between metastatic breast cancer and primary lung cancer can be histologically difficult, and both show an overlapping CK7 þ /CK20À immunoprofile in a majority of cases. The degree of difficulty increases with poorly differentiated tumors. We investigated differential expressions of TTF-1, Napsin A, surfactant apoprotein A, estrogen receptor, GATA-3, mammaglobin, and GCDFP-15 immunostains in 197 pulmonary carcinomas (158 adenocarcinomas, 39 squamous) and 115 invasive mammary carcinomas (91 ductal, 24 lobular type). In mammary carcinomas, estrogen receptor, GATA-3, mammaglobin, and GCDFP-15 were expressed in 74, 72, 64, and 62%, respectively, whereas TTF-1, Napsin A, and surfactant apoprotein A were all negative. The expressions were diffuse in estrogen receptor and GATA-3, and variable in mammaglobin and GCDFP-15. For a combination of estrogen receptor/mammaglobin or GATA-3/mammaglobin, 83% of mammary carcinomas were positive, and the detection rate was not improved by using all three markers. All lung squamous cell carcinomas were negative for all markers studied. TTF-1, Napsin A, and surfactant apoprotein A were positive in 80, 77, and 45% of pulmonary adenocarcinomas. None of the TTF-1-negative tumors expressed surfactant apoprotein A. GCDFP-15 was focally expressed in 2.5% of pulmonary adenocarcinomas, and estrogen receptor was focally expressed in one case (1.2%) of pulmonary adenocarcinoma. When metastasis from breast cancer is suspected in the lung, a combination of either estrogen receptor/mammaglobin or GATA-3/mammaglobin as breast markers, and a combination of TTF-1 and Napsin A as lung markers may be helpful for differentiating between the two. Caution should be taken in the interpretation of GCDFP-15 due to its occasional expression in pulmonary adenocarcinomas.

Utility of small biopsies for diagnosis of lung nodules: doing more with less

“…Furthermore, although napsin A is slightly less sensitive for poorly differentiated adenocarcinomas than TTF-1, it is valuable in occasional adenocarcinomas that are napsin A-positive but TTF-1-negative. [8][9][10] Finally, napsin A stains adenocarcinomas but not small cell carcinomas, 9 a fact that can be helpful when the differential diagnosis of a TTF-1-positive poorly differentiated carcinoma includes small cell carcinoma. Similarly, although p63 is more sensitive for squamous cell carcinomas than CK5/6, the latter is useful when p63 staining is focal, weak or equivocal.…”

Solitary breast metastasis from oestrogen receptor-positive pulmonary adenocarcinoma: report of a case with a potential pitfall

“…The majority of breast cancers are ER-positive, and ER expression is often considered as evidence in favour of mammary origin. Most recently ER-positivity of lung adenocarcinomas has been reported with a range of 0 to 97% [8,9]. Positivity is seen especially with SP1 (and with decreasing frequently with 6F11 or 1D5, the latter of which was first reported not to stain lung adenocarcinomas at all [10]); the staining is generally only focal, and has been more common in non-mucinous lepidic adenocarcinomas [8].…”

Immunohistoochemical evaluation of GATA-3, pAKT and Ki-67 in triple negative breast carcinoma

“…11 We considered less than or equal to 5% staining as negative (score 0). Ductal epithelial cells in benign lobules were considered positive internal controls for GATA3 staining.…”