Coordinated expression of cyclin D1 and LEF-1/TCF transcription factor is restricted to a subset of hepatocellular carcinoma.

Background: While the Wnt pathway has been widely implicated in hepatocarcinogenesis, the role of cyclin D1 as a direct downstream target gene of beta-catenin-lymphoid enhancer factor-1 (LEF-1)/T-cell factor (TCF) signaling is controversely discussed.
Methods: By immunohistochemical analyses we studied the subcellular localization of LEF-1/TCF and cyclin D1 in 162 hepatocellular carcinoma (HCC). Single- and double-label imaging by brightfield and confocal laser scanning microscopy was quantitated and correlated with beta-catenin, the Ki67(+) proliferation fraction (PF), tumor size, grade, the Okuda stage and patient survival.
Results: The frequency of nuclear cyclin D1 expression was 28% and closely correlated with LEF-1/TCF (P<0.0001) and the Ki67(+) PF (P=0.03). Nuclear LEF-1/TCF expression was observed in 52% of all cases, but was also present in 42% of cyclin D1(-) cases. Nuclear beta-catenin was identified in 37% of all HCCs and correlated with LEF-1/TCF (P=0.04). The expression of cyclin D1, LEF-1/TCF or beta-catenin did not correlate with other clinico-pathological data.
Conclusions: A large proportion of HCCs does not appear to be linked to a deregulation of cyclin D1. However, the coordinated expression of cyclin D1 and LEF-1/TCF in some cases suggests the role of cyclin D1 as a Wnt target gene in a subset of HCCs.