Promotion by prolactin of the growth of human breast neoplasms cultured in vitro in the soft agar clonogenic assay

Published on Wednesday, 21 October 2020


The role of prolactin (PRL) in supporting the growth of human breast cancer is still unclear. The ability to grow primary breast cancer specimens in the soft agar clonogenic assay in the absence of serum gave us the opportunity to evaluate the growth-promoting effect of PRL and to compare it to that of estradiol in the same tumor samples.

PRL was tested both at physiological concentrations (20 ng/ml) as well as in pharmacological amounts (200 ng/ml) comparable to circulating blood levels in hyperprolactinemic states.

Estradiol was simultaneously tested in physiological amounts (10(-8)M). In 17 infiltrating ductal carcinomas, the lower dose of PRL stimulated colony formation to 126 +/- 5.2% (SE) of control, while the higher dose increased colony number to 159 +/- 10.4% of control. This latter effect was comparable to that observed with estradiol (159 +/- 8.5% of control). The effect of PRL was more pronounced in estrogen receptor-positive tumors.

Nine of ten estrogen receptor-positive tumors were PRL sensitive, while three of seven estrogen receptor-negative tumors exhibited a clear response to PRL administration. PRL did not stimulate colony formation in a malignant cystosarcoma phylloides and in two benign lesions (fibroadenoma and fibrocystic disease).

We conclude that, at least under the conditions of the soft agar clonogenic assay, PRL exerts a dose-dependent growth-promoting effect on human breast cancer. Such effect is comparable to that of estradiol when PRL is added in concentrations similar to circulating blood levels in hyperprolactinemic patients.


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See also:

- Official Web Site: The Di Bella Method;


- The Di Bella Method (A Fixed Part - Bromocriptine and/or Cabergoline);

- The Di Bella Method (A Fixed Part - Somatostatin, Octreotide, Sandostatin LAR, analogues and/or derivatives);

- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;

- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);

- Publication, 2018 Sep: The over-expression of GH/GHR in tumour tissues with respect to healthy ones confirms its oncogenic role and the consequent oncosuppressor role of its physiological inhibitor, somatostatin: a review of the literature (from Di Bella's Foundation);

- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);

- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);

- The Di Bella Method (A Fixed Part - Cyclophosphamide 50mg tablets and/or Hydroxyurea 500mg tablets, one or two per day);


- The Synergism of Somatostatin, Melatonin, Vitamins Prolactin and Estrogen Inhibitors Increased Survival, Objective Response and Performance Status In 297 Cases of Breast Cancer;

- Complete objective response, stable for 5 years, with the Di Bella Method, of multiple-metastatic carcinoma of the breast;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonin, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma;

- Congenital fibrosarcoma in complete remission with Somatostatin, Retinoids, Vitamin D3, Vitamin E, Vitamin C, Melatonin, Calcium, Chondroitin sulfate associated with low doses of Cyclophosphamide in a 14-year Follow Up.