CA9 and neoplasm: In view of this incomplete status of the field and in order to address and refine the value of the real time qRT-PCR technique compared to IHC, for eventual detection of micrometastases in routine practice, in the present study, we opted a systematic approach to optimize its specificity and assess its validity in reliably detecting lymph node micrometastases, by using for the first time a set of dual molecular tumor-specific markers such as cytokeratin 19 (CK19) and carbonic anhydrase 9 (CA9) in a series of patients with cervical, endometrial, and vulvar cancer.