EGFR expression was closely associated with CA IX expression in agreement with the study by Giatromanolaki et al We have previously reported two important patterns of CA IX staining in NSCLC, mCA IX, which has been proposed to be a marker of tumour cell hypoxia and pCA IX that is associated with a poor prognosis (Swinson et al, 2003). The gene discussed is CA9; the disease is non-small cell lung carcinoma.