[281] Melatonin Receptor in Triple Negative Breast Carcinoma in African-American Women

GM Oprea-Ilies, E Haus, LL Sackett-Lundeen, D Lawson, C Cohen. Emory University, Atlanta, GA; University of Minnesota, Minneapolis, MN; Regions Hospital, St Paul, MN

Background: The pineal hormone melatonin exerts a regulatory function on cell proliferation and an antiproliferative effect on human tumor cell lines and on the growth of human breast cancer (HBC) cell xenografts in vivo. The membrane bound G-protein coupled M1 melatonin receptor is present in HBC cell lines. Activated mediates the growth suppressive action of melatonin on tumor cells. The M1 receptor was identified in ER and PR positive BC. We studied its presence in triple negative breast cancers (TNBC). Melatonine may be of interest in TNBC with no specific adjuvant treatment available.
Design: Tissue microarrays (TMAs) from TNBC from a 6 year period were studied. Tumors that did not show staining for ER, PR and were scored as 0, 1 or 2 with FISH confirmation for non-amplified HER2, were included. Immunohistochemical (IHC) staining was performed for cytokeratin (CK) 5/6, 7,8,14,18,19, vimentin, CD44, survivin, c-kit, p53. Clinico-pathologic data were included . Statistical analysis was performed using Anova.
Results: Of the 107 African-American (AA) patients, 85 had interpretable tumor on the TMAs. The age range was 23-83, with and average age of 50, of which 46% were younger and 54% older than 50 years of age. 80% of AA patients showed positivity for MR1 MR and 20 % were negative. The positivity of melatonin receptor correlated positively with luminal CK7 expression and negatively with the basal CK 5/6. Statically significant data are presented in Table1.

Table 1
VariableDfF-TestP ValueCorr CoeffCorr
All patientsCK5/6852.473430.11960.17011Neg.
Patients>50 yrs oldCK5/6495.913880.0189*0.33431Neg.

Conclusions: 1. 80% of TNBC in AA are positive for melatonin receptor that may indicate responsiveness to growth inhibition by melatonin. 2. Melatonin receptor expression is negatively correlated with basal CK5/6 expression and positively correlated with luminal cytokeratin 7 expression, reflecting possibly different biologic behavior. 3. Survivin, an inhibitor of apoptosis shows a trend to be negatively correlated with melatonin receptors in all patients younger than 50-years of age.
Category: Breast

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 55, Tuesday Morning


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