Correlation of Anti-TULP1 Autoantibodies with Breast Cancer and Autoimmune Retinopathy

Autoantibodies have been implicated in the pathogenesis of autoimmune diseases, including autoimmune retinopathies. Our study aimed to identify retinal autoantigens recognized by serum autoantibodies (AAbs) in patients with visual disturbance. We evaluated 2453 serum samples for anti-retinal AAbs from patients with or without cancer and complaints of visual loss. Anti-TULP1 AAbs were more prevalent in the subset of women with breast cancer and vision loss. Epitope mapping was determined by ELISA using peptides covering the conservative carboxy terminal of TULP1, revealing major lineal epitopes within the sequences 334-341 and 480-488. We found no significant difference in the main epitope recognition between sera from patients with or without breast cancer. Although we show a correlation of anti-TULP1 AAbs with breast cancer, we found no TULP1 protein expression in breast cells, making this association unclear. In the retina, anti-TULP1 AAbs can disrupt the transport of proteins to outer segments and be involved in the degeneration of photoreceptors in a similar fashion to the degeneration induced by <i>TULP1</i> gene mutation. Nevertheless, the strong association of detectable anti-TULP1 AAbs in breast cancer patients with vision problems indicates its potential as a biomarker for cancer-associated autoimmune retinopathy.