miRNA expression of papillary renal neoplasm with reverse polarity (PRNRP) cases

Between 80% and 90% of renal carcinomas are either clear cell renal cell carcinoma or papillary RCC although there are at least 20 other distinct forms of RCC recognised by the World Health Organization (WHO). Emerging or provisional entities have been considered as variants of PRCC, including papillary renal neoplasm with reversed polarity (PRNRP). However, the molecular basis of PRNRP, and miRNA expression profile, is unknown. We used microarray analysis to elucidate the non-coding RNA (ncRNA) profiles of 10 PRNRP cases and compared them with other renal neoplasms. Cases were only considered for this study after fulfilment of strict inclusive histological and immunohistochemical criteria. We used Affymetrix miRNA v.4.0 arrays to elucidate the expression of these samples. Samples were extracted from macrodisected FFPE slides and purified using the Recoverall kit from Ambion