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

Abstract

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.

Primary lung cancer with metastasis to the ipsilateral breast-a case report

“…32,33 CK7 expression was significantly more frequent in pulmonary adenocarcinoma and breast adenocarcinoma than adenocarcinoma of gastrointestinal (GI) origin. 34 In our case CK7 test expressed positivity.…”

“…36 It is reported that CK20 expression was significantly more prevalent in adenocarcinoma that originated in the GI tract than that of pulmonary or breast origin. 34 Despite this fact, CK20 may express positivity in lung adenocarcinoma. 34,[37][38][39] Adenocarcinoma originating in the lungs is typically CK7 positive and CK20 negative.…”

“…34 Despite this fact, CK20 may express positivity in lung adenocarcinoma. 34,[37][38][39] Adenocarcinoma originating in the lungs is typically CK7 positive and CK20 negative. However, this immuno-histochemistry profile is not specific to pulmonary adenocarcinomas; it may also be seen in breast cancer, thyroid cancer, upper gastrointestinal or gynaecological carcinoma, biliary tracts, and pancreatic cancer.…”

Bronchial-pulmonary adenocarcinoma subtyping relates with different molecular pathways

“…43,47 One of the genes that correlate with E2F is Ki67, still a good marker for proliferative index. 48 We obtained statistical significant higher expression of Ki67 in all patterns of adenocarcinoma, indicating active proliferative activity. 49 Another overexpressed gene in this pattern was P53 and some studies indicate that ''a low level of p53 leads to transient growth arrest and cell survival, whereas a high level promotes irreversible apoptosis'', and P53 levels may have oscillations, and it has to be explored as a target for therapy.…”

Lung adenocarcinoma: Sustained subtyping with immunohistochemistry and EGFR, HER2 and KRAS mutational status

“…25---32 All morphological registered patterns comprising this series of lung adenocarcinomas expressed CK7 positivity, without differences (p > 0.05), and predominant negativity for CK20, like other series published in the literature. 8,27,33,34 CK20 was expressed in 3 cases of primary lung adenocarcinoma, with expression of CK7 and TTF1.…”