Spontaneous apoptosis in the intra-ductal component's stroma of breast invasive carcinoma.

Spontaneous apoptosis by in situ detection of DNA fragmentation (DNAf) was investigated in breast invasive ductal carcinoma (IDC) frozen samples removed from 61 untreated patients. The incidence of DNAf was low in carcinoma cells and was mainly detected in the stroma. In the stroma at a distance from carcinoma cells, DNAf was inversely related to estradiol plasma level variations (p=0.01), indicating that it probably remained under physiological hormonal regulation. In the stroma adjacent to carcinoma cells, DNAf was correlated to tumor progression parameters such as the presence of a comedo intra ductal carcinoma (DCIS) component (p=0.001) and axillary lymph node metastasis (p=0.002), suggesting that this stromal compartment more probably represented a tumoral component closely associated to epithelial tumor cells. Therefore, the detection of DNAf in the adjacent stroma of breast carcinoma could help to predict progression in non invasive tumors and also in invasive tumors in those patients without lymph node invasion.

Application of the Spot method to the identification of peptides and amino acids from the antibody paratope that contribute to antigen binding.

Overlapping peptide scans prepared by Spot synthesis have been used to map interaction sites in several systems. Here we report our experience with this approach to identify peptides from the variable parts of anti-hapten, anti-peptide and anti-protein antibodies that retain their specific antigen-binding capacity in the Spot format. In general, the identification by the Spot method of antigen-reactive peptides was confirmed by using soluble peptides which demonstrated antigen-binding capacity in ELISA or Biacore and, biological activity for some peptides derived from anti-CD4 antibodies. The Spot method was also used to map precisely key residues from the antibody paratope. The identification of critical residues from an anti-troponin I antibody of diagnostic interest is reported as well as the compiled results from the analysis of five other antibodies of various specificities. A critical assessment of our results is provided by comparing results obtained by our approach in the mapping of antibody residues critical for antigen binding with data from the literature concerning the structural analysis of antigen-antibody complexes.