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Introduction: Diagnosing Non-Small Cell Lung Carcinoma (NSCLC) by morphology on small biopsy specimens are on demand. With major advances in molecular testing of lung cancers and introduction of targeted therapies, accurate subtyping of NSCLC has become essential. Immunophenotyping with various immunomarkers is helpful in identification of different tumour subtypes. As sparing material for molecular testing is mandatory, a minimalistic Immunohistochemistry (IHC) based diagnostic approach is warranted by means of reliable and accessible immunomarkers. In this study, one immunomarker Thyroid Transcription Factor (TTF1) for glandular and protein40 (p40) for squamous differentiation was applied to maximise the proportion of accurately subtyped NSCLC on small biopsy specimens. Aim: To find utility of TTF1/p40 minimalistic immunopanel in subtyping NSCLC especially those with ambiguous morphology. Materials and Methods: This retrospective observational study was conducted from 15 December 2020 to 5 March 2021 in a tertiary care hospital in which ninety-three (mean age 64.8 years, Male:female ratio 4.8:1) consecutive lung biopsies from suspected lung carcinoma obtained from January 2019 to December 2020 were studied. The morphological diagnosis and diagnosis after application of TTF1 and P40 minimalistic immunopanel was evaluated using chi-square test. The p-value

Thyroid transcription factor 1 (TTF-1) is considered a highly sensitive and specific marker for primary lung adenocarcinoma. However, in recent years retrospective studies of tumor samples have confirmed that, although rare, TTF-1 can also be expressed in colorectal adenocarcinoma. There are a few case reports of patients with TTF-1-positive colon adenocarcinoma in the medical literature but none of TTF-1-positive rectal adenocarcinoma. Here, we present a case of rectal adenocarcinoma with lung metastasis found to be TTF-1 positive on immunohistochemistry. A review and discussion of the available literature is also included.

Thyroid transcription factor 1 (TTF-1) is considered a highly sensitive and specific marker for primary lung adenocarcinoma. However, in recent years retrospective studies of tumor samples have confirmed that, although rare, TTF-1 can also be expressed in colorectal adenocarcinoma. There are a few case reports of patients with TTF-1-positive colon adenocarcinoma in the medical literature but none of TTF- 1-positive rectal adenocarcinoma. Here, we present a case of rectal adenocarcinoma with lung metastasis found to be TTF-1 positive on immunohistochemistry. A review and discussion of the available literature is also included. [ABSTRACT FROM AUTHOR]

It has been suggested that thyroid transcription factor-1 (TTF-1) is frequently expressed in human lung cancer, especially in adenocarcinoma and small cell lung cancer, and the TTF-1 expression is closely related with the expression of surfactant protein. We hypothesized that TTF-1 is expressed in human lung cancer cell lines and its expression might be related to the expression of surfactant protein. To test this, expressions of TTF-1 and surfactant protein A (SP-A) were immunohistochemically evaluated in 16 human lung cancer cell lines. In addition, expressions of mRNAs for TTF-1 and SP-A were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing. As a result, nuclear staining of TTF-1 was observed in two of six adenocarcinoma cell lines, none of seven small cell lung cancer cell lines, and none of three squamous lung cancer cell lines. Among the 16 cell lines, six cell lines (PC3, LC2/Ad, A549, RERF-LC-OK, HI1017, and PC9) expressed significant amounts of mRNA for TTF-1. In contrast, cytoplasmic staining of TTF-1 was observed in five of six adenocarcinoma cell lines, in six of seven small cell lung cancer cell lines, and in all three squamous cell lung cancer cell lines. One of the two adenocarcinoma cell lines those showed positive nuclear staining and cytoplasmic SP-A staining released a significant amount of SP-A in culture supernatant. Our present study demonstrates that the frequency of TTF-1 expression in the nucleus was very low in human lung cancer cell lines; however, their cytoplasmic positivities should be further investigated. [Copyright &y& Elsevier]