BAI3, CDX2 and VIL1: a panel of three antibodies to distinguish small cell from large cell neuroendocrine lung carcinomas

To identify potential markers for distinction of Small cell (SCLC) from large cell neuroendocrine (LCNEC) carcinoma, we have conducted the gene expression profiling on precisely isolated cancer cells and bronchial epithelial cells from these tumours and normal background lung. After statistical analysis and finding highly differentially expressed genes between these tumour groups, we performed qRT-PCR to delineate markers to test at protein level using immunohistochemistry. Markers showing statistical significance at qRT-PCR level were taken forward to stain tissue microarray sections of SCLC and LCNEC to further delineate markers. This resulted in identification of BAI3, CDX2, VIL1 and CD99 as potential candidates. These markers were then taken forward to stain whole sections of tumour sample available in house (University Hospitals Coventry and Warwickshire) which resulted in elimination of CD99. Thus, BAI3, CDX2 and VIL1 were taken further forward to stain tumour samples acquired externally in UK. Four Small cell lung carcinoma, four large cell neuroendocrine carcinoma and seven background lungs were laser microdissected and profiled on Agilent SurePrint G3 human gene expression 8x60K single channel array to identify potential markers for their classification and validated using qRT-PCR and immunohistochemistry.