c-Myb Overexpression in Cytology Smears of Tracheobronchial and Pulmonary Adenoid Cystic Carcinomas

Abstract

Aims: Adenoid cystic carcinoma (AdCC) is a malignant epithelial neoplasm that occurs rarely in the lower respiratory tract (LRT). AdCC at various sites is associated with the novel fusion transcript MYB-NFIB, along with the overexpression of the Myb protein. The expression of the Myb protein in AdCC of the LRT has not been evaluated much. Study Design: Cases of AdCC of the LRT diagnosed on cytology or histology were retrieved from our institutional archives. c-Myb expression was analyzed on immunocytochemistry/immunohistochemistry (ICC/IHC) and was correlated with clinicopathological parameters. Results: Twenty-three samples of AdCC originating from the LRT were included in the study. Four cases were diagnosed on cytology, 3 of which had corresponding histology specimens. The remaining 19 cases had either biopsy or resection. Most of the patients presented with endobronchial mass. The mean age was 49.4 years and a male predominance was seen. ICC and IHC for c-Myb showed positivity in 75 and 59% of the cases, respectively. Western blot was used to validate IHC results. Conclusion: AdCC of the LRT is rare and hence poses diagnostic difficulty. Cytology smears can be utilized for c-Myb ICC. The presence of c-Myb immunopositivity in most cases may possibly make Myb a diagnostic biomarker and a therapeutic target for personalized treatment.

Adenoid cystic carcinoma: A study of 19 cases of salivary and extra‐salivary tumours diagnosed by fine needle aspiration cytology

“…A recurrent translocation involving the PRKD genes has been identified recently in polymorphous adenocarcinoma which may be useful in segregating it from ACC . Recently, tumour specific translocation t(6; 9) with formation of novel fusion transcript; MYB‐NFIB has been detected in ACCs . Immunocytochemistry for c‐Myb can be done on cytology smears.…”

“…with formation of novel fusion transcript; MYB-NFIB has been detected in ACCs. 25,26 Immunocytochemistry for c-Myb can be done on cytology smears. While the sensitivity of MYB IHC is high, specificity is an issue as some of the cytologic differentials of ACC like basaloid squamous carcinomas, EMC, basal cell adenoma/adenocarcinoma and polymorphous adenocarcinoma may occasionally express it.…”

Immunocytochemistry for predictive biomarker testing in lung cancer cytology

“…With the exception of filter preparations, most cytology preparations are feasible for ICC, each with its own advantages and disadvantages (Table ). Among non‐CB preparations, alcohol‐fixed, Papanicolaou direct smears (DSs) and cytospin preparations (CSs) have been most commonly used for ICC, with excellent results, and are the standard media for ICC in many laboratories . Papanicolaou or unstained liquid‐ based cytology (LBC) preparations have also been used for ICC with comparable results .…”

Comparison of conventional smear and liquid-based cytology preparation in diagnosis of lung cancer by bronchial wash and transbronchial needle aspiration

“…[ 20 ] However, in our experience, nuclear stains are easier to interpret on conventional smears also. [ 21 22 23 24 25 ]…”