This article is part of the supplement: 23rd Congress of the International Association for Breast Cancer Research
The in vivo cell kinetics in breast carcinogenesis
1 Department of Pathology, Medical School, University of Ioannina, Ioannina, Greece
2 Department of Histology, Medical School, University of Thessalia, Larisa, Greece
Breast Cancer Res 2001, 3(Suppl 1):A1 doi:10.1186/bcr333
The electronic version of this article is the complete one and can be found online at:
| Received: | 10 May 2001 |
| Published: | 29 May 2001 |
© 2001 BioMed Central Ltd
Background
Disruption of the balance between apoptosis and proliferation is considered to be an important factor in the development and progression of tumor. In this study we determined the in vivo cell kinetics along the spectrum of apparently normal epithelium, hyperplasia, preinvasive lesions and invasive carcinoma, in breast tissues affected by fibrocystic changes in which preinvasive and/or invasive lesions developed, as a model of breast carcinogenesis.
Materials and method
A total of 32 areas of apparently normal epithelium and 135 ductal proliferative and neoplastic lesions were studied. More than one epithelial lesion per case was analyzed. The apoptotic index (AI) and the proliferative index (PI) were expressed as the percentage of TUNEL (TdT-mediated dUTP-nick end-labelling) and Ki-67 positive cells, respectively. The proliferative/apoptotic index (P/A) was calculated for each case.
Results
Statistical analysis demonstrated significant differences among the tissue groups for both indices (P <0.0001). The Als and PIs were significantly higher in hyperplasia than in apparently normal epithelium (P = 0.04 and P = 0.0005, respectively), in atypical hyperplasia than in hyperplasia (P = 0.01 and P = 0.04, respectively) and in invasive carcinoma than in in situ carcinoma (P = 0.0001 and P <0.0001, respectively). The two indices were similar in atypical hyperplasia and in in situ carcinoma. The P/A index increased significantly from normal epithelium to hyperplasia (P = 0.01) and from preinvasive lesions to invasive carcinoma (P = 0.04), whereas it was decreased (NS) from hyperplasia to preinvasive lesions. A strong positive correlation between the Als and the Pls was found (r = 0.83; P <0.0001).
Conclusion
These findings suggest accelerating cell turnover along the continuum of breast carcinogenesis. Atypical hyperplasias and in situ carcinomas might be kinetically similar lesions. In the transition from normal epithelium to hyperplasia and from preinvasive lesions to invasive carcinoma, the net growth of epithelial cells results from a growth imbalance in favour of proliferation. In the transition from hyperplasia to preinvasive lesions there is an imbalance in favour of apoptosis.