EGFR and non-small cell lung carcinoma: Association of positive EGFR immunostaining, as determined by immunohistochemistry (IHC) in NSCLC specimens, with patient sensitivity to EGFR TKI treatment has been studied extensively with both positive (Cappuzzo et al, 2005; Hirsch et al, 2007) and negative (Parra et al, 2004) results reported.