Endocrine Abstracts

Thyroid autoimmunity and BC are strongly related, but the cause of this association is unknown. In BC an increase of lymphoid cell infiltrates may be detected very early during tumor development. BC cells share some antigenic properties similar to those detected in thyroid tissue, as NIS and peroxidase activity and it is possible that in patients with BC and thyroid autoimmunity, should be present serum immunoglobulins reacting with these specific antigenes.

The aim of this study was to evaluate frequency and amount of LI in malignant and normal peritumoral breast tissues, in BC patients with autoimmune thyroid disorders. We suppose that an increased LI in breast tissues of this group of patients, may contribute to explain the association between BC and thyroid autoimmunity.

Study group: 26 BC patients with ductal infiltrating carcinoma (DIC) (aged 26–88 yr, 54.3±12.5 mean ± S.D.) and serum thyroperoxidase antibodies positivity (TPOAb+): 14/26 (53.8%) had evidence of Hashimoto’s thyroiditis (HT). Control group: 30 aged matched patients with DIC and no evidence of thyroid autoimmunity. Malignant and surrounding normal breast tissues were assessed for LI.

LI was scored as absent or scanty (LI A) and moderate or marked (LI M)

LI A was detected in 19/26 DIC (73.1%) with TPOAb+ and LI M in 7 (7/26: 26.9%). All the 14 DIC with HT had LI A. LI A was detected in 25/30 (83%) and LI M in 5/30 (17%) DIC with no thyroid autoimmunity. The difference in LI of DIC with or without thyroid autoimmunity was not significant. LI was generally absent in remote breast tissue in all cases.

The results of the study indicate that in breast cancer the presence of humoral and/or clinical evidence of thyroid autoimmunity is not associated to significative autoimmune morphological changes of malignant or peritumoral breast tissue. In conclusion, a role of breast lymphocytic infiltration in the progress of breast tumorigenesis in BC patients with autoimmune thyroid disorders seems unlike.