Impact of the prolactin levels in breast cancer: a systematic review and meta-analysis

Abstract

Prolactin (PRL) acts stimulating the mammary glands development, and its deregulation has been associated to the emergence of several types of tumors, including breast cancer. Breast cancer represents the most prevalent malignancy in women, and the second cause of death in several countries. This tumor can be arise due to several molecular alterations, among them PRL has been the object of increasing interest from researchers worldwide. Objective: To assess the association between elevated levels of plasma prolactin and breast cancer development. Methods: A total of 158 studies were found in search databases (48 from PubMed, 69 from Scopus, 88 from Cochrane, 25 from Embase and 10 retrieved from the gray literature) after removing duplicates. Of these, 104 studies were excluded after title and abstract reading, and 54 studies were then read in full, of which only 14 were selected for this review because they had evaluated the association between PRL and breast cancer. Meta-analysis was carried out using the relative risk (RR), mean and standard deviation, confidence interval (95% CI), and the total number of patients for each study. Fixed- and random-effect models were used as applicable and, for the analysis. Results: The meta-analysis showed a positive association between elevated levels of PRL and breast cancer occurrence (RR 1.26; 95%CI 1.15–1.37). Additionally, the patient sub-group analyses showed a positive association between PRL and invasive breast cancer (1.42; 1.24–1.60), ER+/PR+ (1.49; 1.23–1.75), and post-menopausal status (1.29; 1.16–1.43). Conclusion: The results showed a positive association between plasma prolactin levels and breast cancer, especially in women with ER+/PR + tumors, of post-menopausal age and those with invasive cancer.

摘要

催乳素（PRL）刺激乳腺发育, 其失调与包括乳腺癌在内的多种肿瘤的发生有关。乳腺癌是女性最常见的恶性肿瘤, 在一些国家甚至是第二大死因。乳腺癌可能是由多种分子改变引起的, 其中PRL越来越受到重视。

目的：评估血浆催乳素水平升高与乳腺癌发生之间的关系。

方法：在去重复后, 在数据库中共找到158项研究（48项来自PubMed, 69项来自Scopus, 88项来自Cochrane, 25项来自Embase, 10项来自灰色文献）。在这些研究中, 104项研究在阅读标题和摘要后被排除在外, 剩下54项研究在全文阅读后, 只有14项入选本研究, 因为这14篇研究评估了PRL与乳腺癌之间的关系。采用相对风险（RR）、平均值和标准差、置信区间（95%CI）以及每项研究的患者总数进行荟萃分析。分析使用了固定效应模型和随机效应模型。

结果：荟萃分析显示PRL水平升高与乳腺癌发生存在正相关（RR 1.26; 95% CI: 1.15-1.37）。此外, 患者亚组分析显示PRL与浸润性乳腺癌（1.42; 95% CI: 1.24-1.60）、ER+/PR+（1.49; 95%CI: 1.23-1.75）和绝经后状态（1.29；1.16-1.43）之间存在正相关。

结论：血浆催乳素水平与乳腺癌呈正相关, 尤其是对于ER+/PR+肿瘤、绝经后年龄和浸润性乳腺癌患者。

Keywords:

• Prolactin
• breast cancer
• meta-analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research received financial support from the Amparo Foundation to São Paulo State Survey – FAPESP (process numbers 2019/01109-2).