The relationship between mast cell infiltration and the expression of PCNA and EGFr in experimental hepatocellular carcinoma of liver and squamous cell carcinoma of stomach in rats.

The expression of PCNA and EGFr in chemically induced hepatocellular carcinoma of liver and squamous cell carcinoma of stomach in rats were immunohistochemically observed. The results showed that the carcinoma cells of both tumors revealed a positive immunreaction to PCNA and EGFr. The histochemical observation of mast cell (MC) in both tumor tissues showed that the amount of MC in the surroundings of tumor cell nests was markedly different. According to the amount of the surrounding MCs the tumor cell nests could be divided into two groups: Group A with abundant MC infiltration and Group B with only scarce or without MC infiltration. The PCNA-positive cells in the tumor cell nests of both groups were calculated respectively. The results revealed that the amount of PCNA-positive cells in the group B was markedly more than that in the group A. The numerical ratio between two groups was 3:1 in the liver carcinoma and 2:1 in the stomach carcinoma approximately. An overexpression of EGFr was observed in tumor tissues of both groups, but there was also a marked difference in the amount of positively expressed cells and in the intensity of their staining reaction between both groups. The positively expressed cells in group B were much more and their staining intensity was much stronger than those in group A. According to the above mentioned results of observation, the expression state of both factors (PCNA and EGFr) was basically identical, suggesting that the MC may possess some inhibitory effect upon the growth rate of tumor cells of the experimental hepatocellular carcinoma of liver and the squamous cell carcinoma of stomach in rats.