Objective      To investigate the biological characteristics of breast primary atypical intraductal hyperplasia fibroblasts (AFs) in tumorigenesis of breast cancer

normal mammary fibroblasts (NFs) and the breast primary cancer-associated fibroblasts (CAFs).       Methods        The primary human breast fibroblasts were isolated by collagenase Ⅰdigestion from normal mammary tissue

atypical intraductal hyperplasia and mammary tumor. The purity of these fibrob

lasts was identified by immunofluorescent staining using the specific first antibody to fibronectin

the fibroblast biomarker. The proliferation and cell cycle for each kind of fibroblasts was detected by MTT assay and flow cytometry. The expression of cyclin D1

p53 and p21

waf1

in the fibroblasts was detected by Western blotting.       Results        More than 95% of the isolated fibroblasts were positive to fibronectin. Comparing with NFs (8.24±2.47)

AFs (16.94±4.77) had higher growth rate and more cells at S-phase of cell cycle (P0.05). However

there were lower growth rate and lesser S-phase cells (P0.05) when compared these parameters in AFs with that in CAFs (33.31±7.90). Similar changes were found on the expression of cyclin D1

p21

waf1

and p53 among AFs

NFs and CAFs.       Conclusion       Different biological characteristics of AFs with NFs and CAFs indicate that AFs are on the way of transformation of NFs to CAFs in the precancerous lesion of breast cancer.