112P Correlation between HER2-negative status and risk of recurrence according to PAM50 score

The prognosis of hormone receptor (HR)-positive early breast cancer (eBC) may vary according to different factors. Human Epidermal Growth Factor Receptor-2 (HER2) is one them. HER2-low population, defined as HER2 1+ or 2+ with negative fluorescent in situ hybridization (FISH), seems have a than the HER2-0. We aimed explore impact HER2-negative status on risk recurrence PAM50 score. conducted retrospective monocentric study including all eBC patients eligible for test, local recommendations. collected each patient tumor characteristics, score, results (ROR) at 10 years and subtype. primary endpoint this was evaluate correlation between (from score 0 FISH) Correlation considered ordinal, both ROR estimated by Pearson coefficient. From October 2016 September 2021, we included 282 median age 58 years. One-hundred ninety eight (70%) had 0, 42 (15%) 2+. There no significant difference subgroup, except higher estrogen progesterone receptors discordance subpopulation. significantly 3 subgroups HER2, 47 [range: 1-89] 50 [15-78] 54 [8-85] (p=0.038). differs subgroups, 0.11 [0.02-0.39] respectively 0.14 [0.03-0.28] [0.04-0.44] (p = 0.013) (without intrinsic low subgroups). increased (Pearson r=0.15, p=0.01, r=0.18, p=0.002, respectively). This suggests Further investigations are needed better describe population larger prospective studies.