Abstract 5345: Cancer stem-like cell markers in stage I and II breast cancer

Abstract

Abstract Background: The number of stem-like cells (SLCs) within the primary tumor is variable. The activity of aldehyde dehydrogenase (ALDH) and the expression of ABCG2 have been reported as potential breast cancer stem-like cell markers. The association between the quantity of SLCs and prognosis remains unclear. Patients and Methods: We prospectively analyzed the expression of ALDH and ABCG2 in 30 patients with invasive ductal carcinomas of the breast. Patients’ mean age was 55.9 ± 14.2 yo. According to clinical stage (CS), three patients were CS I, 19 CS IIa and 8 CS IIb. The mean pathological tumor diameter was 2.2 ± 0.8cm. Eleven patients (39%) had positive lymph node metastasis confirmed by standard histological evaluation (the ALDH expression was analyzed in three macroscopically lymph node metastases from patients #5, #26 and #27 and compared with their matched primary tumors). The ER, PgR and HER2 (IHQ 3+ or 2+ with positive CISH) positive expression rates were 64%, 57% and 35%, respectively. The median percentage of ALDH1+ (ALDEFLUOR®) and ABCG2+ cells within ESA+/Lin- cells were determined by flow cytometry in fresh sampled tumors after tissue digestion. The mammosphere assay (Mammocult@) was studied in 27 samples. The relationship between flow cytometry analyses and clinical and pathological features was analyzed. Results: the median percentage of ESA+/Lin-/ALDH+ cells within the tumor was 5.1 (range 0.2 - 31.6). We found an inverse correlation between the percentage of ESA+/ALDH+ cells within the tumor and the pathological tumor diameter (r= −0.4; p= 0.04). No association between the ALDH expression and all the others clinical and pathological features was observed. The analysis of ALDH expression in three lymph node metastasis demonstrated that the percentage of ALDH+ cells is very similar to their matched primary tumors (case #5 0.8% and 1.7%; case 26 0.3% and 0.7%; case 27 5.9% and 5.9%). The median percentage of ESA+/Lin-/ABCG2+ cells within the primary tumor was 7.4% (range 1.5 - 61.1). We did not observe any association between ABCG2 expression and all the clinical and pathological parameters observed. The median number of mammospheres formed was 12/104 cells (range 3 - 60). There was no correlation between ALDH and ABCG2 expression and the ability to form mammosphere. Discussion and Conclusion: we demonstrated the percentage of ALDH positive cells is inversely correlated to tumor diameter in stage I and II breast carcinomas. The lymph node metastasis is similar to the primary tumor in terms of ALDH expression. Although it has been demonstrated that this subpopulation of cells has stem-like properties the intrinsically variation and its relationship with other prognostic factors remains unclear. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5345. doi:1538-7445.AM2012-5345