Co-localisation of Glandular and Squamous Cell Markers in Non-small Cell Lung Cancer

Accurate classification of lung carcinomas is crucial for selecting appropriate and adequate chemotherapy treatment. In this study, glandular (adenocarcinoma), and squamous cell differentiation were examined in non-small cell lung carcinoma (NSCLC) without obvious light-microscopic signs of squamous and glandular differentiation.

All lung tumours diagnosed as NSCLC (n=61), without obvious squamous or glandular features, were obtained by bronchial biopsy or core biopsy supported by computed tomography. They were diagnosed during 1996-2009, at the Department of Pathology, Gävle Hospital, Sweden. The tumours were examined immunohistochemically with antibodies against CK5/6, p63 (squamous cell markers) and carcinoembryonic antigen (CEA) (adenocarcinoma cell marker). Double immunostaining (p63/CEA) was also performed on individual tumours.

The tumours originated from 36 males and 25 females, aged 54-83 years. Pure squamous cell differentiation (CK5/6 positive only) occurred in 34.4% (n=21) tumours and pure adenocarcinoma cell differentiation (CEA positive only) was present in 14.9% (n=9). Tumours with both squamous and adenocarcinoma features (CK5/6 and CEA positive) were most prevalent (47.5%, n=29). Two tumours (3.3%) were negative with both stains (and also synaptophysin negative). Double immunostaining (p63/CEA) revealed that squamous and adenocarcinoma markers were co-localised in cells in certain tumours.

Co-localisation of squamous and adenocarcinoma markers in the same tumour cell suggests that additional analyses for novel biomarkers of specific lung cancer types may subsequently lead to a refined treatment choice for patients with the goal of improving clinical outcomes.