BACKGROUND: FEC (5-FU+epirubicin+cyclophosphamide) therapy has been used as 
adjuvant chemotherapy for breast cancer patients with nodes positive. The aim of 
this study was to evaluate host immunity and side effects of the FEC therapy. 
The effect of oral administration of Lentinus edodes mycelia (LEM) was also 
observed.
METHODS: Ten patients were enrolled in this study. The treatment with 5-FU (500 
mg/m2), epirubicin (75 mg/m2) and cyclophosphamide (500 mg/m2) was administered 
every 21 days for 2 cycles, and LEM (9 g/day po) was administered during the 2nd 
cycle.
RESULTS: NK cell activity and the number of white blood cells decreased on the 
7th day after the therapy, and they recovered on the 21st day. However, this NK 
cell activity and the number of white blood cells didn't decrease when the FEC 
therapy was used with LEM po.
CONCLUSIONS: FEC 75 therapy has made some impacts on host immunity, and LEM with 
the FEC 75 therapy might have prevented host immunity.