Serum Prolactin Levels as a Novel, Practical Marker for Predicting Malignant Diseases of the Breast

Background and objective Prolactin (PRL) has a high specificity toward breast cancer (BC), making it a valuable marker in both diagnosis and prognosis. In this study, we aimed to compare serum PRL levels between pre- and post-menopausal women with BC, as well as normal reference values. We also investigated the association of various risk factors with PRL levels in women with BC. Methods The study involved adult women diagnosed with BC based on clinical features and tissue histopathology receiving treatment at a tertiary care center in Pune, India. General and demographic information, anthropometric measurements (height, weight, and BMI), menstrual status (age at menarche and menopausal state), clinical presentation (signs and symptoms), duration of symptoms, and parity were recorded by using a pre-tested proforma based on hospital records or in-person interviews. Serum PRL was measured by the RIA method (sandwich assay). Results A total of 67 women (average age: 47.5 ± 11.8 years; 33 of them post-menopausal) with BC were included in the study. The participants had an average BMI of 24.9 ± 3.5 kg/m², and 26 (39%) of them were overweight. The majority of women had BC stage IIA disease, involvement of the right side or upper outer quadrant, and had attained menarche after 14 years of age; 47 women had a BC duration of >3 months. Seven women were nulliparous, and the remaining had given birth to their first child before the age of 26 years. The average serum PRL level among the participants was 9.27 ± 7.62 ng/mL, with higher levels found in post-menopausal women compared to pre-menopausal women (11.08 vs. 7.51 ng/mL, respectively; p=0.08). Women with a higher stage and greater duration of disease had significantly higher serum PRL levels (p<0.001 for both). When compared with reference values, pre-menopausal women showed significantly lower (6.25 vs. 10.9, respectively; p=0.001) and post-menopausal women showed significantly higher (8.55 vs. 5.95; p=0.004) serum PRL levels. A positive correlation was found between serum PRL and age at the time of birth of the first child (p=0.068). Conclusions Based on our findings, PRL is an important hormone in the development of BC in women. Therapeutic modulation of PRL may be a realistic and novel approach to curing human BC, either administered alone or in combination with conventional treatments.