1. Risk evaluation in breast cancer: a preliminary study of pre-metastatic niche in 252 lymphnodes A.Ieni, A. Simone, G. Neri, V. Barresi, G. Giuffrè, B. Adamo, N. Caristi, F. Colonnese, M.A. Gioffrè Florio, V. Adamo, G. Tuccari University of Messina - Italy Department of Human Pathology National Congress SIAPEC – IAP Florence 7-9 September

2. Background Bone marrow-derived hematopoietic progenitor cells (HPCs) seem to participate in early spread of cancer cells through the formation of a peculiar and highly organized micro-environment for distant tumour growth called “Pre-Metastatic Niche (PMN)”. The identification of such HPCs in PMNs is emerging as a key step in the assessement of risk for metastases.

3. In order to identify HPCs of the premetastatic niche in breast cancer, we have analyzed 252 lymphnodes(17 of which pN1a), obtained from 25 patients (mean age 58.6; age range 47-79 yrs), surgically treated in the period 1998-2000 for ductal invasive carcinomas. The mean follow-up was 84.2 mo. (range 36–136). Materials

4. Methods Samples have been fixed in 10% neutral buffered formalin for 12-72 hrs and included in paraffin at 56 °C; 4 m  thick serial sections were pre-treated in microwave owen in 10 mM citric acid, ph 6.0 and incubated overnight with the folllowing poly/monoclonal antisera: a. VEGF-R1 (Santa Cruz Biothechnology 1:400) b. CD 133 (Abgent 1:80) c. CD 117 (DAKO 1:500) d. CD-34 (DAKO 1:50)

5. Results Results VEGF-R1

6. Results CD 133

7. Results CD 117

8. Results CD 34

9. Results In lymphnodes, clusters of immunoreactive cells were always evident with CD 117 and CD 34. A different amount of lymphnode immunopositivity was found with VEGR-R1 and CD 133 antibodies in relation to different metastatic sites. In particular, breast cancer cases with a follow-up history characterized by a metastatic spread in lungs, liver and central nervous system were more immunoreactive than those with bone localization. Seventeen lymphnodes classified as pN1a showed no immunoreactivity.

10. The clinical significance of “node negative” breast carcinomas needs to be further investigated, since the identification of HPCs able to predict possible, imminent or future, spread to other sites becomes mandatory. The immunomorphological research for PMNs in the lymphnode microenvironment could have significant clinical implications for the breast cancer treatment. Conclusions