Profile of thyroid hormones in breast cancer patients

Abstract

Estrogen involvement in breast cancer has been established; however, the association between breast cancer and thyroid diseases is controversial. Estrogen-like effects of thyroid hormone on breast cancer cell growth in culture have been reported. The objective of the present study was to determine the profile of thyroid hormones in breast cancer patients. Serum aliquots from 26 patients with breast cancer ranging in age from 30 to 85 years and age-matched normal controls (N = 22) were analyzed for free triiodothyronine (T 3 F), free thyroxine (T 4 F), thyroid-stimulating hormone (TSH), antiperoxidase antibody (TPO), and estradiol (E 2 ). Estrogen receptor ß (ERß) was determined in tumor tissues by immunohistochemistry. Thyroid disease incidence was higher in patients than in controls (58 vs 18%, P < 0.05). Subclinical hyperthyroidism was the most frequent disorder in patients (31%); hypothyroidism (8%) and positive anti-TPO antibodies (19%) were also found. Subclinical hypothyroidism was the only dysfunction (18%) found in controls. Hyperthyroidism was associated with postmenopausal patients, as shown by significantly higher mean T 3 and T 4 values and lower TSH levels in this group of breast cancer patients than in controls. The majority of positive ERß tumors were clustered in the postmenopausal patients and all cases presenting subclinical hyperthyroidism in this subgroup concomitantly exhibited Erß-positive tumors. Subclinical hyperthyroidism was present in only one of 6 premenopausal patients. We show here that postmenopausal breast cancer patients have a significantly increased thyroid hormone/ E 2 ratio (P < 0.05), suggesting a possible tumor growth-promoting effect caused by this misbalance.

Triiodothyronine and breast cancer

“…Epidemiologic studies have shown a possible association between thyroid dysfunction and BC. Postmenopausal BC patients have been reported to have a significant increase in THs, suggesting that an imbalance between estradiol (E2) and T3 fosters the development of BC [44][45][46] . Conversely, hyperthyroidism has been associated with a reduction in the incidence of BC [47] .…”

“…As shown by Tosovic et al [56] , high levels of T3 in postmenopausal women positively correlate with the risk of BC in a doseresponse manner. In the case of hyperthyroidism, this correlation was found in postmenopausal women but not in premenopausal woman who had BC [44] . These postmenopausal women with BC had a significant increase in their thyroid/estradiol ratio, suggesting that an imbalance between E2 and T3 fosters the development of BC [44] .…”

“…In the case of hyperthyroidism, this correlation was found in postmenopausal women but not in premenopausal woman who had BC [44] . These postmenopausal women with BC had a significant increase in their thyroid/estradiol ratio, suggesting that an imbalance between E2 and T3 fosters the development of BC [44] . Conversely, hyperthyroidism has been associated with a reduction in the incidence of BC [47] .…”

“…Experimental studies have shown that THs influence both the differentiation of normal breast cells [44] and the proliferation of BC cells [44,50,51] . The proliferative effect of T3 has been demonstrated in various types of cancer.…”

Relationship between Breast Cancer and Levels of Serum Thyroid Hormones and Antibodies: a Meta-analysis

“…Full--text ar+cles assessed for eligibility (n =21) Figure.1) (Turken et al, 2003;Cengiz et al, 2004;Kuijpens et al, 2005;Saraiva et al, 2005;Giustarini et al, 2006;Ditsch et al, 2010;Ali et al, 2011;Szychta et al, 2013) . Tables 1 and 2 show the characteristics and data of all 8 studies included in our analysis.…”