['Hepatoma-derived growth factor (HDGF)-related proteins (HRPs) comprise a family of six members and are characterised by a conserved HATH domain. Among the family members, HDGF was the first to be identified as a mitogenic factor and shown to play an important role in hepatocellular carcinoma pathogenesis. The aim of the present study is to examine the relevance of HDGF-related protein-3 (HRP-3), another member of the HRP family in hepatocellular carcinoma (HCC).', 'HRP-3 expression in HCC tissues was measured by quantitative reverse transcriptase PCR, western blot and immunohistochemistry analysis. The biological consequences of overexpression and knockdown of HRP-3 in HCC cell lines were studied in vitro and in vivo.', 'Expression of HRP-3 mRNA and protein was shown to be highly upregulated in HCC tissues. While knockdown of HRP-3 by small interference RNAs failed to affect anchorage-dependent growth of HCC cells, it inhibited anchorage-independent growth of HCC cells in vitro and xenograft tumour growth in vivo. Further, knockdown of HRP-3 was shown to sensitise HCC cells to anoikis. Moreover, HRP-3 specifically activated the extracellular-signal-regulated kinase (ERK) pathway without affecting c-Jun N-terminal kinase (JNK), p38, AKT and signal transducer and activator of transcription 3 (STAT3). Importantly, inhibition of the ERK pathway diminished HRP-3-mediated protection of HCC cells from anoikis. Finally, knockdown of HRP-3 was shown to enhance apoptosis of HCC cells induced by multiple chemotherapeutic drugs.'] Is hDGF-related protein-3 required for anchorage-independent survival and chemoresistance in hepatocellular carcinomas?