Evaluation of plectin-1 immunohistochemical staining in human non-small cell lung cancer

e22118 Background: Plectin-1 (PLEC1), a known scaffolding protein, impacts signaling pathways and has been found to be up-regulated and redistributed to the cell membrane in tumor cells. The redistribution of PLEC1 has shown promise as a novel molecular imaging biomarker in experimental systems. The purpose of this study was to examine the variation of PLEC1 staining in human non-small cell lung cancer (NSCLC). Methods: 142 NSCLC samples from 2001–2003 were obtained from pathology archives and placed into tissue microarray (TMA) format. TMA sections were stained with anti-PLEC1 antibody. A total PLEC1 immunohistochemical (IHC) staining score was obtained by multiplying the intensity of PLEC1 staining, scored 0 through 3, by the percent of tumor cells showing membrane staining, scored 1 for <25%, 2 for 25%-75% and 3 for >75%. The samples were then grouped into low (0–2), intermediate (3–5) or high (6- 9) membrane expression and analyzed for clinical correlations to tumor type and pathological staging. Results: A total of 125 samples were successfully stained for PLEC1. In all NSCLC subgroups, there was variability of PLEC1 staining. Approximately 50% of cases showed intermediate to high staining. There was a trend of lower PLEC1 staining as the tumor stage advanced (p=0.1). There appeared to be no significant variations of PLEC1 staining when compared to gender of the patients. Conclusions: These findings are the first to show that a significant number of human NSCLC exhibit strong expression of PLEC1 in the cell membrane. As this biomarker is being developed for molecular imaging modalities in other tumor types, it may have potential to be of use in the non-invasive detection of disease or therapeutic efficacy monitoring in NSCLC. [Table: see text] No significant financial relationships to disclose.