PAX8 is a member of the paired box
(PAX) family of transcription factors. Members of this gene family typically
encode proteins which contain a paired box domain, an octapeptide, and a
paired-type homeodomain. This family plays critical roles during fetal
development and cancer growth. PAX8 is involved in kidney cell differentiation,
thyroid development, or thyroid dysgenesis. Studies show that expression of the
PAX8 gene was found in 89% of analyzed tumor samples. The expression of the PAX8
target genes were found in all normal renal samples. PAX8 has been shown to be
expressed in three of the most common types of renal cell carcinoma including
clear cell, chromophobe and papillary carcinoma but negative for uroepithelial
carcinoma of renal pelvis. PAX8 stains nuclei exclusively and performs well in
formalin-fixed paraffinembedded tissues. PAX8 has been shown to be a superior
marker compared to the Renal Cell Carcinoma Marker
(RCC).