The rate at which interesting thyroid-related papers are published is astonishing. Here another paper with a handsome contribution from the Thyroid Research Group in Cardiff. Hopefully, slowly, a more comprehensive and coherent picture of thyroid and related diseases appears out of the mists.
In this abstract, the very first sentence is really quite a surprise (to me). And it really makes me question the whole issue of what the TPO antibodies do, why they are present, and what the appropriate interpretations of test numbers might be.
Int J Cancer. 2013 Sep 30. doi: 10.1002/ijc.28493. [Epub ahead of print]
Does thyroid peroxidase provide an antigenic link between thyroid autoimmunity and breast cancer?
Muller I, Giani C, Zhang L, Grennan-Jones FA, Fiore E, Belardi V, Rosellini V, Funel N, Campani D, Giustarini E, Lewis MD, Bakhsh AD, Roncella M, Ghilli M, Vitti P, Dayan CM, Ludgate ME.
Thyroid Research Group, Institute of Molecular © Experimental Medicine, School of Medicine, Cardiff University, UK; Department of Endocrinology, University of Pisa, Italy.
Women with breast cancer (BC) and anti thyroid peroxidase (TPO) autoantibodies (TPOAb) have a better prognosis than women lacking TPOAb. Sera from women with TPOAb displayed immunoreactivity to BC tissue by immunofluorescence that was not apparent in women without TPOAb. We hypothesize a BC/thyroid shared antigen that provides a target for humoral or cell-mediated immune activity; candidates include the sodium/iodide symporter (NIS, expressed in thyroid and BC), cross-reacting epitopes in TPO and lactoperoxidase (LPO) or TPO itself. Since the association is with TPOAb, we investigated TPO expression in BC, breast peri-tumoral tissue (PT), other tissues (tumoral and not) and thyroid as positive control. Transcripts for known and novel TPO isoforms were detected in BC (n=8) and PT (n=8) but at approximately 104 fold lower than in thyroid while in non-BC tumours (n=5) they were at the limit of detection. TPO was expressed also in adipose tissue (n=17), 103 fold lower than in thyroid. Full length TPO (Mr 105-110 kDa) was detected in western blots in the majority of examined tissues; pre-absorption of the TPO antibody with recombinant TPO (but not LPO) reduced the signal, indicating specificity. The same occurred with some lower molecular weight bands, which could correspond to smaller TPO transcript isoforms, present in all samples. In conclusion TPO is weakly expressed in BC and other tissues; this could partly explain the high frequency and protective role of TPOAb in BC patients. Further studies will investigate tissue specificity, function and immunogenicity of the novel TPO variants (some BC-specific) identified. © 2013 Wiley Periodicals, Inc.
Copyright © 2013 UICC.
Alternative Splicing, Antigen, Breast cancer, Thyroid autoimmunity, Thyroid peroxidase
[PubMed - as supplied by publisher]
Image: Illustration of antibody showing constant and variable portions, light and heavy chains and disulphide bonds.
30 August 2008 : Recreated jpg originally uploaded by Muntasir Alam : Author DigitalShuttermonkey