Zhang, Yingjie

Abstract1q gain (+1q) is the most common high‐risk cytogenetic abnormality (HRCA) in patients with multiple myeloma (MM). However, its prognostic value remains unclear in the era of novel agents. Here, we retrospectively analyzed the impact of +1q on the outcomes of 934 patients newly diagnosed with MM. +1q was identified in 53.1% of patients and verified as an independent variate for inferior overall survival (OS) (hazard ratio, 1.400; 95% confidence interval, 1.097–1.787; p = .007). Concurrence of other HRCAs (particularly t(14;16) and del(17p)) further exacerbated the outcomes of patients with +1q, suggesting prognostic heterogeneity. Thus, a risk‐scoring algorithm based on four risk variates (t(14;16), hypercalcemia, ISS III, and high LDH) was developed to estimate the outcomes of patients with +1q. Of the patients, 376 evaluable patients with +1q were re‐stratified into low (31.6%), intermediate (61.7%), and high risk (6.7%) groups, with significantly different progression‐free survival and OS (p < .0001), in association with early relapse of the disease. The prognostic value of this model was validated in the CoMMpass cohort. While attaining undetectable MRD largely circumvented the adverse impact of +1q, it scarcely ameliorated the outcome of the patients with high risk, who likely represent a subset of patients with extremely poor survival. Hence, patients with +1q are a heterogeneous group of high‐risk patients, therefore underlining the necessity for their re‐stratification. The proposed simple risk‐scoring model can estimate the outcomes of patients with +1q, which may help guide risk‐adapted treatment for such patients.

Hereditary renal cystic diseases are characterized by defects in primary cilia of renal tubular epithelial cells and abnormality of tubular epithelium, which ultimately result in the development of renal cysts. However, the mechanism leading from abnormality of the tubular epithelium to cystogenesis is not well understood. In this report, we demonstrate a critical role for Robo2 in regulating epithelial development, including ciliogenesis, polarization, and differentiation. We found that Robo2 deficiency results in cystic kidneys, and the cyst cells showed defective cilia and polarity defects in tubular epithelium. The cyst cells, less than terminally differentiated, continue to proliferate. We further established that Robo2 works with p53 as well as polarity and ciliary proteins (Par3, PKCς, ZO-2, and Claudin-2) to regulate these processes. Robo2 binds to Baiap2 (also known as IRSp53) through the IRSp53/MIM homology domain in renal epithelial cells. This binding allows Robo2 to phosphorylate MDM2 at Ser166 via Baiap2 and maintain p53 homeostasis. Disruption of the Robo2-Baiap2 complex causes MDM2 to be subjected to dephosphorylation, leading to a high level of active p53, and initiated p53-mediated cellular senescence via p21 and decreased the expression of ZO-1, ZO-2, PKCς, Par3, and Claudin-2 proteins, resulting in defects in epithelial development, including ciliogenesis, polarization, and differentiation. Importantly, double knockout of Robo2 and p53 rescued all the epithelial defects in kidneys compared with those in Robo2 -knockout kidneys. Taken together, the present results demonstrate that Robo2 deficiency causes renal cystic disease, which is largely dependent on defective Robo2-Baiap2 integrated signaling in kidneys.