JC Chen

The aggregation of amyloidogenic proteins is infamous for being highly chaotic, with small variations in conditions sometimes leading to large changes in aggregation rates. Using the amyloidogenic protein IAPP (islet amyloid polypeptide protein, also known as amylin) as an example, we show that a part of this phenomenon may be related to the formation of micellelike oligomers at specific critical concentrations and temperatures. We show that pyrene fluorescence can sensitively detect micellelike oligomer formation by IAPP and discriminate between micellelike oligomers from fibers and monomers, making pyrene one of the few chemical probes specific to a prefibrillar oligomer. We further show that oligomers of this type reversibly form at critical concentrations in the low micromolar range and at specific critical temperatures. Micellelike oligomer formation has several consequences for amyloid formation by IAPP. First, the kinetics of fiber formation increase substantially as the critical concentration is approached but are nearly independent of concentration below it, suggesting a direct role for the oligomers in fiber formation. Second, the critical concentration is strongly correlated with the propensity to form amyloid: higher critical concentrations are observed for both IAPP variants with lower amyloidogenicity and for native IAPP at acidic pH in which aggregation is greatly slowed. Furthermore, using the DEST NMR technique, we show that the pathway of amyloid formation switches as the critical point is approached, with self-interactions primarily near the N-terminus below the critical temperature and near the central region above the critical temperature, reconciling two apparently conflicting views of the initiation of IAPP aggregation.

OBJECTIVES: The objective of the current review was to synthesize the literature on intersectionality relative to disparities across the cancer care continuum. A model to support future intersectional cancer research was proposed. METHODS: Web-based discovery services and discipline-specific databases were queried for both peer-reviewed and gray literature. Study screening and data extraction were facilitated through the Covidence software platform. RESULTS: Among 497 screened studies, 28 met study inclusion criteria. Most articles were peer-reviewed empirical studies (n = 22) that focused on pre-diagnosis/screening (n = 19) and included marginalized racial/ethnic (n = 22) identities. Pre-cancer diagnosis, sexual orientation and race influenced women's screening and vaccine behaviors. Sexual minority women, particularly individuals of color, were less likely to engage in cancer prevention behaviors prior to diagnosis. Race and socioeconomic status (SES) were important factors in patient care/survivorship with worse outcomes among non-white women of low SES. Emergent themes in qualitative results emphasized the importance of patient intersectional identities, as well as feelings of marginalization, fears of discrimination, and general discomfort with providers as barriers to seeking cancer care. CONCLUSIONS: Patients with intersectional identities often experience barriers to cancer care that adversely impact screening, diagnosis, treatment, as well as survivorship. The use of an "intersectional lens" as a future clinical and research framework will facilitate a more multidimensional and holistic approach to the care of cancer patients.

Importance: Elevated allostatic load (AL) has been associated with adverse socioenvironmental stressors and tumor characteristics that convey poor prognosis in patients with breast cancer. Currently, the association between AL and all-cause mortality in patients with breast cancer is unknown. Objective: To examine the association between AL and all-cause mortality in patients with breast cancer. Design, Setting, and Participants: This cohort study used data from an institutional electronic medical record and cancer registry at the National Cancer Institute Comprehensive Cancer Center. Participants were patients with breast cancer diagnoses (stage I-III) between January 1, 2012, through December 31, 2020. Data were analyzed from April 2022 through November 2022. Exposure: AL was expressed as a summary score calculated by assigning 1 point for biomarkers in the worst sample quartile. High AL was defined as AL greater than the median. Main Outcomes and Measures: The main outcome was all-cause mortality. A Cox proportional hazard models with robust variance tested the association between AL and all-cause mortality. Results: There were 4459 patients (median [IQR] age, 59 [49-67] years) with an ethnoracial distribution of 3 Hispanic Black patients (0.1%), 381 non-Hispanic Black patients (8.5%), 23 Hispanic White patients (0.5%), 3861 non-Hispanic White patients (86.6%), 27 Hispanic patients with other race (0.6%), and 164 non-Hispanic patients with other race (3.7%). The mean (SD) AL was 2.6 (1.7). Black patients (adjusted relative ratio [aRR], those with 1.11; 95% CI, 1.04-1.18), single marital status (aRR, 1.06; 95% CI, 1.00-1.12), and those with government-supplied insured (Medicaid aRR, 1.14; 95% CI, 1.07-1.21; Medicare aRR, 1.11; 95% CI, 1.03-1.19) had a higher adjusted mean AL than those who were White, married/living as married, or privately insured, respectively. Adjusting for sociodemographic, clinical, and treatment factors, high AL was associated with a 46% increase in mortality risk (hazard ratio [HR], 1.46; 95% CI, 1.11-1.93) over low AL. Similarly, compared with patients in the first AL quartile, those in the third quartile (HR, 1.53; 95% CI, 1.07-2.18) and the fourth quartile (HR, 1.79; 95% CI, 1.16-2.75) had significantly increased risks of mortality. There was a significant dose-dependent association between increased AL and a higher risk of all-cause mortality. Furthermore, AL remained significantly associated with higher all-cause mortality after adjusting for the Charlson Comorbidity Index. Conclusions and Relevance: These findings suggest increased AL is reflective of socioeconomic marginalization and associated with all-cause mortality in patients with breast cancer.