Podoplanin(+) tumor lymphatics are rate limiting for breast cancer metastasis
PLOS BIOLOGY
Authors: Chen, Yang; Keskin, Doruk; Sugimoto, Hikaru; Kanasaki, Keizo; Phillips, Patricia E.; Bizarro, Lauren; Sharpe, Arlene; LeBleu, Valerie S.; Kalluri, Raghu
Abstract
Metastatic dissemination employs both the blood and lymphatic vascular systems. Solid tumors dynamically remodel and generate both vessel types during cancer progression. Lymphatic vessel invasion and cancer cells in the tumor-draining lymph nodes (LNs) are prognostic markers for breast cancer metastasis and patient outcome, and tumor-induced lymphangiogenesis likely influences metastasis. Deregulated tumor tissue fluid homeostasis and immune trafficking associated with tumor lymphangiogenesis may contribute to metastatic spreading; however, the precise functional characterization of lymphatic endothelial cells (LECs) in tumors is challenged by the lack of specific reagents to decipher their rate-limiting role in metastasis. Therefore, we generated novel transgenic mice (PDPN promoter-driven Cre recombinase transgene [PDPN-Cre] and PDPN promoter-driven thymidine kinase transgene [PDPN-tk]) that allow for the identification and genetically controlled depletion of proliferating podoplanin (Pdpn)-expressing LECs. We demonstrate that suppression of lymphangiogenesis is successfully achieved in lymphangioma lesions induced in the PDPN-tk mice. In multiple metastatic breast cancer mouse models, we identified distinct roles for LECs in primary and metastatic tumors. Our findings support the functional contribution of primary tumor lymphangiogenesis in controlling metastasis to axillary LNs and lung parenchyma. Reduced lymphatic vessel density enhanced primary tumor lymphedema and increased the frequency of intratumoral macrophages but was not associated with a significant impact on primary tumor growth despite a marked reduction in metastatic dissemination. Our findings identify the rate-limiting contribution of the breast tumor lymphatic vessels for lung metastasis.
Impact of a Pregabalin Step Therapy Policy Among Medicare Advantage Beneficiaries
PAIN PRACTICE
Authors: Suehs, Brandon T.; Louder, Anthony; Udall, Margarita; Cappelleri, Joseph C.; Joshi, Ashish V.; Patel, Nick C.
Abstract
Background: Managed healthcare organizations often utilize formulary management strategies such as prior authorization and step therapy to guide appropriate medication use and to control medication expenditures. The objective of this study was to examine clinical and economic outcomes associated with implementation of a pregabalin step therapy (ST) policy among Medicare Advantage Prescription Drug (MAPD) members. Methods: Pharmacy and medical claims data from Humana (restricted cohort; ST policy implemented 01/01/2009) and Thomson Reuters MarketScan (R) (unrestricted cohort) were analyzed for MAPD members aged 65 to 89 years receiving treatment for painful diabetic peripheral neuropathy (pDPN), postherpetic neuralgia (PHN) or fibromyalgia (FM). Difference-in-differences (DID) was used to examine year-over-year changes in disease-related and all-cause utilization and costs. Regression analyses examined medication utilization and healthcare expenditures after controlling for between-group compositional differences. Results: We identified 13,911 members in the restricted cohort and matched to members from unrestricted health plans. FM (51.0%) and pDPN (41.8%) were the most common diagnoses. Members in the unrestricted cohort were older and had a greater level of comorbidity than members in the restricted cohort. The restricted cohort demonstrated greater year-over-year decrease in pregabalin utilization and increase in year-over-year gabapentin utilization compared with the unrestricted cohort. ST restriction was associated with an increase in disease-related pharmacy costs and a decrease in total medical costs for the restricted cohort compared with the unrestricted cohort. There was no difference between cohorts in total healthcare cost. Conclusion: After controlling for differences in age and comorbidity burden between the groups, implementation of a pregabalin ST restriction was associated with increased disease-related pharmacy costs and decreased total medical costs; however, there was no net difference in total healthcare cost or total pharmacy cost.