Purpose: To investigate the potential roles that p16 (CDKN2A) and RB activation have in sensitization to MEK inhibitor in resistant KRAS-mutant non-small cell lung cancer cells (NSCLC) in vitro and in vivo.Experimental Design: Cell viability was measured with MTS assays. Effects of administration of radiation and combination drug treatments were evaluated by clonogenic assay, flow cytometry, and Western blots. DNA repair was assessed using immunofluorescent analysis. Finally, lung cancer xenografts were used to examine in vivo effects of drug treatment and radiation therapy.Results: In this study, we showed that sensitivity to MEK inhibitor correlated to the RB/p16/CDK4 pathway and knockdown of RB induced resistance in cell lines sensitive to MEK inhibitor. Also, overexpression of p16 and inhibition of CDK4 had the ability to sensitize normally resistant cell lines. Our data indicated that the MEK inhibitor (trametinib, GSK112012) cooperated with the CDK4/6 inhibitor (palbociclib, PD0332991) to strongly reduce cell viability of KRAS-mutant NSCLCs that were resistant to the MEK inhibitor in vitro and in vivo. In addition, we report for the first time that resistance of KRAS-mutant NSCLCs to MEK inhibitor is, at least partly, due to p16 mutation status, and we described a drug combination that efficiently reactivates the RB tumor suppressor pathway to trigger radiosensitizing effects, apoptosis, and cell-cycle arrest.Conclusions: Our findings suggest that MEK inhibitor in combination with CDK4/6 inhibitor has significant anti-KRASmutant NSCLC activity and radiosensitizing effect in preclinical models, potentially providing a novel therapeutic strategy for patients with advanced KRAS-mutant NSCLCs.

IMPORTANCEThe expansion of Medicaid sought to fill gaps in insurance coverage among low-income Americans. Although coverage has improved, little is known about the relationship between Medicaid expansion and breast cancer stage at diagnosis. OBJECTIVE To review the association of Medicaid expansion with breast cancer stage at diagnosis and the disparities associated with insurance status, age, and race/ethnicity. DESIGN, SETTING, AND PARTICIPANTS This cohort study used data from the National Cancer Database to characterize the relationship between breast cancer stage and race/ethnicity, age, and insurance status. Data from 2007 to 2016 were obtained, and breast cancer stage trends were assessed. Additionally, preexpansion years (2012-2013) were compared with postexpansion years (2015-2016) to assess Medicaid expansion in 2014. Data were analyzed from August 12, 2019, to January 19, 2020. The cohort included a total of 1 796 902 patients with primary breast cancer who had private insurance, Medicare, or Medicaid or were uninsured across 45 states. MAIN OUTCOMES AND MEASURES Percent change of uninsured patients with breast cancer and stage at diagnosis, stratified by insurance status, race/ethnicity, age, and state. RESULTSThis study included a total of 1 796 902 women. Between 2012 and 2016, 71 235 (4.0%) were uninsured or had Medicaid. Among all races/ethnicities, in expansion states, there was a reduction in uninsured patients from 22.6% (4771 of 21 127) to 13.5% (2999 of 22 150) (P < .001), and in nonexpansion states, there was a reduction from 36.5% (5431 of 14 870) to 35.6% (4663 of 13 088) (P = .12). Across all races, there was a reduction in advanced-stage disease from 21.8% (4603 of 21 127) to 19.3% (4280 of 22 150) (P < .001) in expansion states compared with 24.2% (3604 of 14 870) to 23.5% (3072 of 13 088) (P = .14) in nonexpansion states. In African American patients, incidence of advanced disease decreased from 24.6% (1017 of 4136) to 21.6% (920 of 4259) (P < .001) in expansion states and remained at approximately 27% (27.4% [1220 of 4453] to 27.5% [1078 of 3924]; P = .94) in nonexpansion states. Further analysis suggested that the improvement was associated with a reduction in stage 3 diagnoses. CONCLUSIONS AND RELEVANCEIn this cohort study, expansion of Medicaid was associated with a reduced number of uninsured patients and a reduced incidence of advanced-stage breast cancer. African American patients and patients younger than 50 years experienced particular benefit. These data suggest that increasing access to health care resources may alter the distribution of breast cancer stage at diagnosis.

Radiotherapy has the widest application to esophageal squamous cell carcinoma (ESCC) patients. Factors associated with DNA damage repair have been shown to function in cell radiosensitivity. Human positive cofactor 4 (PC4) has a role in nonhomologous end joining (NHEJ) and is involved in DNA damage repair. However, the clinical significance and biological role of PC4 in cancer progression and cancer cellular responses to chemoradiotherapy (CRT) remain largely unknown. The aim of the present study was to investigate the potential roles of PC4 in the radiosensitivity of ESCC. In this study, we showed that knockdown of PC4 substantially increased ESCC cell sensitivity to ionizing radiation (IR) both in vitro and in vivo and enhanced radiation-induced apoptosis and mitotic catastrophe (MC). Importantly, we demonstrated that silencing of PC4 suppressed NHEJ by downregulating the expression of XLF in ESCC cells, whereas reconstituting the expression of XLF protein in the PC4-knockdown ESCC cells restored NHEJ activity and radioresistance. Moreover, high expression of PC4 positively correlated with ESCC resistance to CRT and was an independent predictor for short disease-specific survival of ESCC patients in both of our cohorts. These findings suggest that PC4 protects ESCC cells from IR-induced death by enhancing the NHEJ-promoting activity of XLF and could be used as a novel radiosensitivity predictor and a promising therapeutic target for ESCCs.

Cholecystocolic fistula (CCF), a connection between the gallbladder and neighboring colon, is a rare entity with little consensus as to the optimal surgical management. Existing case reports have described both open and laparoscopic repairs. We describe the first reported case of a successful robotic repair of a CCF in a 50-year-old woman diagnosed with cholangitis 5 years prior to surgery. The patient had a longitudinal follow-up by a single surgeon, allowing for early diagnosis and repair. This case also includes radiographic imaging over 5 years during the index hospitalization and preoperative workup. This allows for a glimpse into the natural pathogenesis of this disease. After robotic surgery, the patient made a complete recovery with no postoperative complications.

Uncovering novel growth modulators for non-small cell lung cancer (NSCLC) may lead to new therapies for these patients. Previous studies suggest Nit1 suppresses chemically induced carcinogenesis of the foregut in a mouse model. In this study we aimed to determine the role of Nit1 in a transgenic mouse lung cancer model driven by a G12D Kras mutation. Nit1 knockout mice (Nit1−/−) were crossed with KrasG12D/+ mice to investigate whether a G12D Kras mutation and Nit1 inactivation interact to promote or inhibit the development of NSCLC. We found that lung tumorigenesis was suppressed in the Nit1-null background (Nit1−/−:KrasG12D/+). Micro-CT scans and gross tumor measurements demonstrated a 5-fold reduction in total tumor volumes compared to Nit1+/+KrasG12D/+ (p<0.01). Furthermore, we found that Nit1 is highly expressed in human lung cancer tissues and cell lines and use of siRNA against Nit1 decreased overall cell survival of lung cancer cells in culture. In addition, cisplatin response was enhanced in human lung cancer cells when Nit1 was knocked down and Nit1−/−:KrasG12D/+ tumors showed increased sensitivity to cisplatin in vivo. Together, our data indicate that Nit1 may play a supportive role in the modulation of lung tumorigenesis and represent a novel target for NSCLCs treatment.