Abstract PS3-25: Quantitation of serum thioredoxin 1 could mitigate difficulty to detect breast cancer from dense breasts by mammography

Abstract Background: Even though almost half of women have dense breasts (DB), the density of breasts has been an obstacle to detect breast cancer (BC) correctly by the gold standard of screening, mammography. It is strongly recommended to take consideration of breast density in analyzing mammogram. We have reported the possibility of serum level of thioredoxin 1 (Trx1) as a novel means to assess the risk of BC regardless of various conditions of breasts. In present study, we have evaluated how serum level of Trx1 can mitigate the difficulty to detect BC from dense breast by mammography. Methods: We have generated monoclonal antibodies against Trx1 and developed an ELISA kit that quantitates Trx1 in serum. The level of Trx1 was determined in each serum from BC patients (n=106) who had been confirmed as BC by various examinations including mammography as well as surgery. Each Trx1 level was analyzed with corresponding patient’s mammography results such as patterns, asymmetry, shapes, margin, and density. The analyzed results were compared with those from other biomarker tests including CA15-5 and CEA to evaluate the clinical validity of Trx1 in this study. Each test was duplicated two times, and test results were analyzed by ROC analysis, one-way ANOVA tests, and unpaired t-tests.Results: Most of BC patients (82.6%, n=86) was classified as mammography pattern 3 and 4, and BI-RADS score higher than 4 (74.0%, n=77). More than half of patients’ breast density was in high density group (54.8%, n=57), whereas 5.8% of iso density (n=6) and 39.4% of not determined (n=41). The blood Trx1 levels of patients were higher than the cut-off value of 14 U/ml indicating BC regardless of characteristics of breasts. Although other breast cancer biomarker tests such as CA15-3 and CEA could not identify BC, Trx1 level could correctly detect BC even in the cases that mammography could not show the mass clearly. The sensitivity/specificity of mammography and Trx1 test were 75.2%/74.0% and 96.2%/99.0%, respectively. When mammography and Trx1 test were combined, the whole sensitivity/specificity was 99.3%/100.0%. Conclusion: Even though it is obvious that larger size of further study necessary, the serum Trx1 level showed that it could identify BC in dense breasts easily. These results indicated that serum Trx1 level could efficiently mitigate the difficulty to detect BC from dense breasts by mammography. Keywords: Thioredoxin 1, Breast cancer, Dense breast, Diagnostics, Sensitivity, Specificity, Blood Citation Format: Kyoung Hoon Suh, Bo Bae Choi, Youn Ju Lee, Je Ryoong Kim, Jin Sun Lee, Young Kim. Quantitation of serum thioredoxin 1 could mitigate difficulty to detect breast cancer from dense breasts by mammography [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-25.