CA9 and vulvar carcinoma: The relatively increased sensitivity of CA9 expression using the RT-PCR in the latter study compared to the present data may be attributable to the fact that in the study of vulvar carcinoma [21], about 50% of the tested lymph nodes were designated as sentinel nodes, representing the first nodes in the lymphatic flow from the primary lesion, and it is expected to be the first site of a metastatic process.