Breast carcinoma is a multifaceted-etiology malignancy. The presence of estrogen (ER), progesterone (PR), and HER2 (human epidermal growth factor receptor 2) receptors in breast carcinoma tissue has therapeutic implications. Recent studies indicate that pineal hormone melatonin by its receptor melatonin 1 (MT1) also influences the development and growth of breast cancer cells. The aim of this cross-sectional study was to elucidate the expression pattern of MT1 receptor in relation to estrogen, progesterone, and HER2 receptors in breast carcinoma. Two groups (receptor positive and triple negative) of breast carcinoma were taken. For comparison, normal mammary tissue was used as control. Immunohistochemistry was carried out using anti-melatonin receptor 1A antibody. Membranous/cytoplasmic expression was seen more than the nuclear expression in the cancerous tissue. Positive correlation of the MT1 expression was seen with ER, PR, and HER 2 receptor. Higher MT1 receptor expression was seen in the receptor-positive cases in comparison with triple-negative cases, which might signify melatonin deficiency in the former, leading to reactive increase in cell receptors. No correlation of MT1 expression with Ki67 index or lymph node status in both receptor-positive and triple-negative cases was found. Normal mammary tissue mainly showed cytoplasmic MT1 immunoreactivity of epithelial cells (ducts and acini), myoepithelial cells, and lining epithelium of blood vessels. Receptor-positive cases would, therefore, benefit from the use of melatonin as supporting therapy. This indicates that melatonin receptor status can be used as an independent pathologic indicator to evaluate breast carcinoma tissue, and melatonin receptor status may help to determine treatment protocols.

中文翻译：

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褪黑激素在乳腺癌中的作用

乳腺癌是一种多方面病因的恶性肿瘤。乳腺癌组织中雌激素 (ER)、孕激素 (PR) 和 HER2（人表皮生长因子受体 2）受体的存在具有治疗意义。最近的研究表明，松果体激素褪黑激素通过其受体褪黑激素 1 (MT1) 也影响乳腺癌细胞的发育和生长。这项横断面研究的目的是阐明 MT1 受体与雌激素、孕激素和 HER2 受体在乳腺癌中的表达模式。取两组（受体阳性和三阴性）乳腺癌。为了比较，使用正常乳腺组织作为对照。使用抗褪黑激素受体 1A 抗体进行免疫组织化学。在癌组织中，膜/细胞质表达比核表达更多。MT1 表达与 ER、PR 和 HER 2 受体呈正相关。与三阴性病例相比，受体阳性病例中 MT1 受体表达更高，这可能表明前者缺乏褪黑激素，导致细胞受体反应性增加。在受体阳性和三阴性病例中均未发现 MT1 表达与 Ki67 指数或淋巴结状态相关。正常乳腺组织主要表现为上皮细胞（导管和腺泡）、肌上皮细胞和血管内衬上皮的细胞质MT1免疫反应性。因此，受体阳性病例将受益于使用褪黑激素作为支持疗法。