Increased mast cells in hepatocellular carcinoma and intrahepatic cholangiocarcinoma

BACKGROUND/AIMS: Human mast cells are categorized into those positive only for tryptase (MC(T)) and those positive for both tryptase and chymase (MC(TC)). METHODS: We investigated mast cells in "normal" livers (n=13), hepatocellular carcinoma (HCC) (n= 49) and intrahepatic cholangiocarcinoma (ICC) (n= 44) by double immunostaining and quantitative morphometry. RESULTS: In "normal" livers, mast cells were located in portal tracts, and to a lesser extent in the sinusoids. In HCC, mast cells were noted in tumoral sinusoids and fibrous septa. In ICC, many mast cells were present in tumoral stroma. Morphometry showed that densities of mast cells in HCC and ICC were significantly higher than those in "normal" livers. The density of mast cells in ICC (57.6+/-62.4/mm2) was significantly higher than that in HCC (9.32+/-12.9/mm2). The density of sinusoidal mast cells was significantly higher in HCC (1.79+/-2.35/mm2) than in "normal" livers (0.13+/-0.07/mm2). The density of stromal mast cells was significantly higher in ICC (57.6+/-62.4/mm2) than that of portal tracts in "normal" livers (28.4+/-7.0/mm2). MC(T) and MC(TC) were approximately 20% and 80%, respectively, being consistent in any anatomical compartments. CONCLUSIONS: Mast cells increase during carcinogenesis in HCC and ICC, and they may play a role in fibrosis or tumor immunology in HCC and ICC.