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Keywords:

  • EpCAM;
  • prognosis;
  • renal cell carcinomas;
  • papillary RCC;
  • chromophobe RCC;
  • tissue microarray

Objective

  • To evaluate the expression and prognostic value of epithelial cell adhesion/activating molecule (EpCAM) in a large set of renal cell carcinomas (RCCs) using a tissue microarray (TMA) approach.

Material and Methods

  • We studied the immunohistochemical expression and overexpression of EpCAM on TMAs containing formalin-fixed, paraffin-embedded samples of 948 patients with documented renal tumours.
  • EpCAM expression was defined as the presence of a specific membranous staining in >5% of the tumour cells.
  • EpCAM overexpression was specified by calculating a total staining score (score range 0–12) as the product of a proportion score and an intensity score, and defined as a score >4.

Results

  • Of 948 cases, 927 (97.8%) were evaluable morphologically (haematoxylin and eosin stain). EpCAM expression was found in 233/642 (36.3%), 126/155 (81.3%), 54/68 (78.3%), 17/45 (37.8%), 13/30 (43.3%) of clear-cell RCC, papillary RCC (pRCC), chromophobe RCC (cpRCC), oncocytomas and other unclassified tumour types, respectively.
  • Log-rank tests showed a significantly longer overall survival (OS [P = 0.047]) and a trend of EpCAM expression to be associated with a longer progression-free survival (PFS) in all RCC entities (P = 0.065).
  • EpCAM overexpression was significantly correlated with a better PFS in all RCC subtypes, cpRCC and pRCC (P = 0.011, 0.043 and 0.025, respectively).
  • In multivariate analysis EpCAM overexpression was an independent marker for longer PFS in all RCC entities as well as in high grade RCC (P = 0.009 and P = 0.010, respectively).

Conclusions

  • The histological subtypes associated with a high rate of EpCAM expression were cpRCC and pRCC.
  • This retrospective analysis demonstrated a trend towards longer OS and PFS for all major RCC subtypes.
  • EpCAM expression had significant prognostic value in patients with cpRCC and pRCC. Furthermore, EpCAM overexpression in high grade RCC may be a helpful marker for prognostication.