CA9 and cervical carcinoma: The purpose of the present work was to challenge the view that HIF-1α and CAIX may be useful biomarkers of tumor hypoxia and hypoxia-induced tumor aggressiveness in cervical carcinoma by searching for possible associations between HIF-1α expression, CAIX expression, fraction of hypoxic tissue, and lymph node metastasis in tumors of two human cervical carcinoma xenograft lines.