Wang, A. H.

Abstract Background The cerebellar dentate is a known site of iron accumulation and tau deposition in progressive supranuclear palsy (PSP); however, detailed iron distribution and localized volume and shape changes remain unclear across PSP clinical variants. Objective The study aimed to clarify details about regional susceptibility distribution, volume, and shape deformation in the cerebellar dentate across PSP clinical variants. Methods Sixty‐seven PSP patients, including 31 PSP‐Richardson syndrome, 12 PSP‐parkinsonism, 10 PSP‐progressive gait freezing, and 14 PSP‐cortical variants (PSP‐frontal, PSP‐speech/language, and PSP‐corticobasal syndrome), and 31 healthy controls underwent 3 Tesla magnetic resonance imaging to reconstruct quantitative susceptibility maps. Manual dentate segmentation was performed to extract magnetic susceptibility and volume adjusted for total intracranial volume. Shape deformation was assessed using Deformetrica atlas construction. Group comparisons were evaluated with Kruskal–Wallis tests and receiver operating characteristic analysis. Results Patients with PSP‐Richardson syndrome, PSP‐parkinsonism, and PSP‐cortical variants showed significantly increased dentate susceptibility compared with controls ( P < 0.05). Patients with PSP‐progressive gait freezing showed no significant susceptibility differences. Volume loss was most prominent in PSP‐cortical variants, bilaterally, and PSP‐Richardson syndrome, left hemisphere only ( P < 0.05). Shape analysis revealed subregion‐specific deformation patterns, especially in the anterior and posterior deformation in PSP‐progressive gait freezing and the ventroanterior deformation in PSP‐cortical variants. Conclusions The PSP clinical variants had different patterns of susceptibility, volume, and shape metrics, reflecting distinct neurodegenerative patterns of the cerebellar dentate. These findings contribute to our understanding of the neurobiology of PSP and may help to improve phenotypic differentiation of PSP clinical variants. © 2026 International Parkinson and Movement Disorder Society.

1002 Background: Physical activity is a modifiable breast cancer risk factor, perhaps mediating risk reduction through regulation of estrogen metabolism. Evidence regarding effect of physical activity is conflicting partly because breast cancer is a heterogenous constellation of different tumor subtypes with differing etiologies. No prospective study has examined the relationship between physical activity and breast cancer incidence based on ER/PR status or histological subtype. Objective: Examine effect of physical activity on breast cancer incidence based on ER/PR status and histological subtypes of breast cancer. Methods: The Iowa Women’s Health Study is a prospective cohort study of postmenopausal women (N=41,837). Physical activity was self-reported on baseline questionnaire, and three levels (high, medium and low) were defined. Breast cancer incidence, histologic subtype and ER/PR status, through 18 years of follow-up, were ascertained by linkage with the Iowa SEER Cancer Registry. Cox proportional hazards models were used to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs) of breast cancer, adjusting for other breast cancer risk factors. Results: During 554,819 person-years of follow-up, 2548 incident cases of breast cancer were observed. High physical activity was associated with decreased risk for breast cancer (RR 0.91, 95 % CI 0.81–1.01) compared to low activity. The protective effect was most marked in ER+/PR− (RR 0.66, CI 0.46–0.94), intermediate in ER−/PR− (RR 0.80, CI 0.56–1.15), weakest in ER+/PR+ (RR 0.94, CI 0.81–1.08), and elevated in ER-/PR+ (RR 1.42, CI 0.67–3.01) tumors. Higher physical activity was also associated with a decreased risk of invasive ductal/lobular carcinoma (RR 0.90, CI 0.80–1.02), but not with invasive breast cancer with a favorable histology (RR 1.19, CI 0.78–1.81). Conclusions: Higher physical activity was associated with a 10% decreased risk of breast cancer. Unexpectedly, risk reduction was most marked in PR- tumors, particularly ER+/PR-, and the more aggressive histologic forms. Further studies are needed to confirm these findings, and also evaluate other risk factors based on ER/PR status and histological subtypes. No significant financial relationships to disclose.