BACKGROUND: Disruption of the balance between apoptosis and proliferation is considered to be an important factor in the development and progression of @entity5 . In the present study we determined the in vivo cell kinetics along the spectrum of apparently normal epithelium, @entity1373 , preinvasive @entity189 , in breast tissues affected by @entity3923 in which preinvasive and/or invasive lesions developed, as a model of @entity0 . MATERIALS AND METHODS: A total of 32 areas of apparently normal epithelium and 135 ductal proliferative and @entity1313 were studied. More than one epithelial lesion per case were analyzed. The apoptotic index (AI) and the proliferative index (PI) were expressed as the percentage of @entity10730 -mediated @entity1977 -nick end-labelling (TUNEL) and Ki-67-positive cells, respectively. The PI/AI (P/A index) was calculated for each case. RESULTS: The AIs and PIs were significantly higher in @entity1373 than in apparently normal epithelium (P = 0.04 and P = 0.0005, respectively), in @entity1373 than in @entity1373 (P = 0.01 and P = 0.04, respectively) and in @entity189 than in in situ @entity189 (P < 0.001 and P < 0.001, respectively). The two indices were similar in @entity1373 and in in situ @entity189 . The P/A index increased significantly from normal epithelium to @entity1373 (P = 0.01) and from preinvasive lesions to @entity189 (P = 0.04) whereas it was decreased (non-significantly) from @entity1373 to preinvasive lesions. A strong positive correlation between the AIs and the PIs was found (r = 0.83, P < 0.001). CONCLUSION: These findings suggest accelerating cell turnover along the continuum of @entity0 . @entity1373 and in situ @entity189 might be kinetically similar lesions. In the transition from normal epithelium to @entity1373 and from preinvasive lesions to @entity189 the net growth of epithelial cells results from a growth imbalance in favour of proliferation. In the transition from @entity1373 to preinvasive lesions there is an imbalance in favour of apoptosis.

In vivo cell kinetics in XXXX .

@entity10730 :: ('1791', 'Gene') :: ['TdT'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast carcinogenesis'] @entity1313 :: ('MESH:D001932', 'Disease') :: ['neoplastic lesions'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumours'] @entity1373 :: ('MESH:D006965', 'Disease') :: ['hyperplasia', 'Atypical hyperplasias', 'atypical hyperplasia'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinomas', 'carcinoma', 'invasive carcinoma', 'lesions and invasive carcinoma'] @entity1977 :: ('CHEBI:17625', 'Chemical') :: ['dUTP'] @entity3923 :: ('MESH:D005348', 'Disease') :: ['fibrocystic changes']
@entity0 :: (MESH:D001943,Disease) :: ['breast carcinogenesis']
