Mutation in the EGFP domain of LDL receptor-related protein 6 (LRP6(R611C)) is associated with hypercholesterolemia and early-onset atherosclerosis, but the mechanism by which it causes disease is not known. Cholesterol uptake was examined in cells from LRP6(+/-) mice and LRP6(R611C) mutation carriers. Splenic B cells of LRP6(+/-) mice have significantly lower LRP6 expression and low-density lipoprotein (LDL) uptake than those of the wild-type littermates. Although similar levels of total LRP6 were found in lymphoblastoid cells (LCLs) of LRP6(R611C) mutation carriers and those of the unaffected family member, LDL uptake was significantly lower in the mutant cells. Mutant and wild-type receptors show similar affinities for apolipoprotein B at neutral pH. LRP6 colocalized with LDL and was coimmunoprecipitated with NPC1 (Niemann-Pick disease type C1), an endocytic regulator of LDL trafficking. However, the cellular localization of LRP6 in the mutant cells shifted from cell surface to late endosomes/lysosomes. Plasma membrane expression levels of LRP6(R611C) was lower compared to wild-type receptor and declined to a greater extent in LDL-rich medium. Further examinations revealed lower efficacy of apolipoprotein B dissociation from LRP6(R611C) compared to wild-type receptor at an acidic pH. These studies identify LRP6 as a receptor for LDL endocytosis and imply that R611C mutation results in reduced LRP6 membrane expression and decreased LDL clearance. Based on our findings, we conclude that the increased affinity of the mutant receptor for LDL in acidic pH leads to their impaired dissociation in late endosomes, which compromises their recycling to the plasma membrane.
The aim of this study was to evaluate outcomes of patients with stage III endometrial adenocarcinoma treated with surgery followed by adjuvant chemotherapy and vaginal cuff brachytherapy.
Methods
We retrospectively identified 83 patients treated for 1988 International Federation of Gynecology and Obstetrics (FIGO) stage III endometrial adenocarcinoma at our institution between 2003 and 2010. All patients underwent comprehensive surgical staging. Adjuvant therapy was carboplatin and paclitaxel for 6 cycles and vaginal cuff brachytherapy. For analysis, patients were grouped into type I (FIGO grade 1–2 endometrioid histology, n = 41) or type II (FIGO grade 3, clear cell or papillary serous histology, n = 42) disease. Forty-three patients (52%) had node-positive disease, with similar node-positive rates for type I (n = 21, 51.2%) and type II (n = 22, 52.4%).
Results
The median follow-up was 38.6 months. There were no isolated vaginal failures. The estimated 3-year disease-free survival (DFS) and overall survival (OS) for type I versus type II were 92.4% versus 58.0% (P = 0.001) and 97.2% versus 65.8% (P = 0.002), respectively. The 3-year DFS and OS for node negative versus node positive were 85.0% versus 63.6% (P = 0.02) and 84.2% versus 78.0% (P = 0.02), respectively. Associations between type I histology and node-negative disease with improved DFS and OS persisted on multivariate analysis.
Conclusions
Our institutional approach of adjuvant chemotherapy and vaginal cuff brachytherapy for stage III endometrial cancer seemed acceptable for patients with low-risk histology or node-negative disease. In contrast, higher rates of failure among those with high-risk histology and/or node-positive disease support intensification of therapy in these subsets.
To evaluate our institutional experience combining carboplatin-paclitaxel (C/T) chemotherapy with high-dose-rate (HDR) intra-vaginal brachytherapy (IVB) following comprehensive surgical staging in localized uterine serous carcinoma (USC).Institutional chart review identified 56 patients with FIGO 2009 stage I-II USC treated between 2000-2010. Patients underwent total hysterectomy, bilateral salpingo-oopherectomy, and comprehensive surgical staging including pelvic and para-aortic lymph node dissection, omentectomy, and peritoneal cytology. Chemotherapy was 6 cycles of C/T, and the IVB dose was 14 Gy in 2 fractions, prescribed to 0.5 cm from the cylinder surface. Kaplan-Meier methods were used to estimate recurrence-free survival (RFS) and overall survival (OS).The median follow-up time was 49 months (range: 9-145). The 5-yr RFS and OS were 85% and 93%, respectively. In all cases of recurrence (n = 8), the first site of failure was extra-pelvic. There were no isolated vaginal recurrences, however, there was one vaginal apex recurrence recorded at 19 months in a patient with simultaneous lung metastases. Thus, the 2-year vaginal RFS was 98%.Excellent vaginal/pelvic control rates were observed. Further study of HDR brachytherapy dose and fractionation in combination with chemotherapy is worthwhile.
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