Furthermore, ABCG2 mRNA levels were significantly lower in adenomas and carcinomas compared to the level in unaffected tissue from the same individuals and compared to tissue from healthy individuals (P<0.0001 for all).
Cytoplasmatic accumulation of ABCG2 in poorly differentiated carcinomas might coincide with malfunctioning of PI3K-signaling pathways during tumor progression.
Strikingly, we observed that the expression of podoplanin and ABCG2 within a single pre-neoplastic OE lesion significantly correlate with subsequently developing multiple and multifocal carcinomas, thus to some extent demonstrating the concept of field cancerization.
ABCG2 is one of at least three so-called multidrug resistant ABC transporters expressed in humans, and its activity is associated with decreased efficacy of anti-cancer agents in several carcinomas.