Differential expression of high-affinity melatonin receptors (MT1) in normal and malignant human breast tissue.
Melatonin is a pineal hormone that strongly inhibits the growth of breast cancer cells in vitro and in vivo. We report thefirst use of immunohistochemical analysis to determine the distribution of the high-affinity melatonin receptor subtype, MTI, in human breast tissue, the hypothalamic suprachiasmatic nucleus, and skin. The MT1 antibody, which is specific for the cytoplasmic portion of the receptor, produced cytoplasmic staining in normal-appearing breast epithelial cells and ductal carcinoma cells; stromal cells, myoepithelial cells, and adipocytes were nonreactive. The majority of nonneoplastic samples (13/19 [68%]) were negative to weakly positive, while moderate to strong reactivity was seen in most cancer samples (49/65 [75%]). Thus, although MT1 receptors were detectable in normal and malignant breast epithelium, high receptor levels occurred more frequently in tumor cells (P < .001), and tumors with moderate or strong reactivity were more likely to be high nuclear grade (P < .045). These findings may have implications for the use of melatonin in breast cancer therapy.
Dillon
Dionne C
DC
State University of New York at Buffalo School of Medicine, USA.
Easley
Samantha E
SE
Asch
Bonnie B
BB
Cheney
Richard T
RT
Brydon
Lena
L
Jockers
Ralf
R
Winston
Janet S
JS
Brooks
John S
JS
Hurd
Thelma
T
Asch
Harold L
HL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000033:anatomy & histology / Q000378:metabolism* / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002278:Carcinoma in Situ / Q000378:metabolism* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism* / Q000473:pathology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D044094:Receptors, Melatonin; D012867:Skin / Q000378:metabolism; D013493:Suprachiasmatic Nucleus / Q000378:metabolism
D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D044094:Receptors, Melatonin