TP53 structure-function relationships in metastatic castrate-sensitive prostate cancer and the impact of APR-246 treatment.

PURPOSE: Despite well-informed work in several malignancies, the phenotypic effects of TP53 mutations in metastatic castration-sensitive prostate cancer (mCSPC) progression and metastasis are not clear. We characterized the structure-function and clinical impact of TP53 mutations in mCSPC. PATIENTS AND METHODS: We performed an international retrospective review of men with mCSPC who underwent next-generation sequencing and were stratified according to TP53 mutational status and metastatic burden. Clinical outcomes included radiographic progression-free survival (rPFS) and overall survival (OS) evaluated with Kaplan-Meier and multivariable Cox regression. We also utilized isogenic cancer cell lines to assess the effect of TP53 mutations and APR-246 treatment on migration, invasion, colony formation in vitro, and tumor growth in vivo. Preclinical experimental observations were compared using t-tests and ANOVA. RESULTS: Dominant-negative (DN) TP53 mutations were enriched in patients with synchronous (vs. metachronous) (20.7% vs. 6.3%, p < 0.01) and polymetastatic (vs. oligometastatic) (14.4% vs. 7.9%, p < 0.01) disease. On multivariable analysis, DN mutations were associated with worse rPFS (hazards ratio [HR] = 1.97, 95% confidence interval [CI]: 1.31-2.98) and overall survival [OS] (HR = 2.05, 95% CI: 1.14-3.68) compared to TP53 wild type (WT). In vitro, 22Rv1 TP53 R175H cells possessed stronger migration, invasion, colony formation ability, and cellular movement pathway enrichment in RNA sequencing analysis compared to 22Rv1 TP53 WT cells. Treatment with APR-246 reversed the effects of TP53 mutations in vitro and inhibited 22Rv1 TP53 R175H tumor growth in vivo in a dosage-dependent manner. CONCLUSIONS: DN TP53 mutations correlated with worse prognosis in prostate cancer patients and higher metastatic potential, which could be counteracted by APR-246 treatment suggesting a potential future therapeutic avenue.

Cross-Sectional Association of Patient Language and Patient-Provider Language Concordance with Video Telemedicine Use Among Patients with Limited English Proficiency.

BACKGROUND: Telemedicine's dramatic increase during the COVID-19 pandemic elevates the importance of addressing patient-care gaps in telemedicine, especially for patients with limited English proficiency. OBJECTIVE: To examine the associations of patient language and patient-provider language concordance with telemedicine visit type (video versus telephone visit). DESIGN: Cross-sectional automated data study of patient-scheduled primary care telemedicine appointments from March 16, 2020, to October 31, 2020. SETTING: Northern California integrated healthcare delivery system. PARTICIPANTS: All 22,427 completed primary care telemedicine visits scheduled by 13,764 patients with limited English proficiency via the patient portal. MEASUREMENTS: Cross-sectional association of electronic health record-documented patient language (Spanish as referent) and patient-provider language concordance with patients' choice of a video (versus telephone) visit, accounting for patient sociodemographics, technology access, and technology familiarity factors. RESULTS: Of all patient-scheduled visits, 34.5% (n = 7747) were video visits. The top three patient languages were Spanish (42.4%), Cantonese (16.9%), and Mandarin (10.3%). Adjusting for sociodemographic and technology access and familiarity factors and compared to patients speaking Spanish, video visit use was higher among patients speaking Cantonese (OR = 1.34, 95% CI: 1.18-1.52), Mandarin (OR = 1.33, 95% CI: 1.16-1.52), or Vietnamese (OR = 1.27, 95% CI: 1.09-1.47), but lower among patients speaking Punjabi (OR = 0.75, 95% CI: 0.75, 0.62-0.91). Language concordance was associated with lower video visit use (OR = 0.86, 95% CI: 0.80-0.93) and moderated associations of speaking Spanish, Cantonese, and Korean with video visit use. In addition, for all language groups, those with prior video visit use were more likely to re-use video visits compared to those with no prior use (p < .05 for all languages except Hindi with p = 0.06). CONCLUSIONS: Among linguistically diverse patients with limited English proficiency, video telemedicine use differed by specific language. Disaggregating patient subpopulation data is necessary for identifying those at greatest risk of being negatively impacted by the digital divide.

Assessment of Lymphoma and Other Hematologic Malignancies Training Needs Among Radiation Oncology Residents: a Brief Report.

The role of radiation therapy (RT) varies across hematologic malignancies (HM). Radiation oncology (RO) resident comfort with specific aspects of HM patient management is unknown. The International Lymphoma RO Group (ILROG) assessed resident HM training opportunities and interest in an HM away elective. RO residents (PGY2-5) in the Association of Residents in RO (ARRO) database (n = 572) were emailed an anonymous, web-based survey in January 2019 including binary, Likert-type scale (1 = not at all, 5 = extremely, reported as median [interquartile range]), and multiple-choice questions. Of 134 resident respondents (23%), 86 (64%) were PGY4/5 residents and 36 (27%) were in larger programs (≥ 13 residents). Residents reported having specialized HM faculty (112, 84%) and a dedicated HM rotation (95, 71%). Residents reported "moderate" preparedness to advocate for RT in multidisciplinary conferences (3 [2-3]); make HM-related clinical decisions (3 [2-4]); and critique treatment planning (3 [2-4]). They reported feeling "moderately" to "quite" prepared to contour HM cases (3.5 [3-4]) and "quite" prepared to utilize the PET-CT five-point scale (4 [3-5]). Overall, residents reported feeling "moderately" prepared to treat HM patients (3 [2-3]); 24 residents (23%) felt "quite" or "extremely" prepared. Sixty-six residents (49%) were potentially interested in an HM away elective, commonly to increase comfort with treating HM patients (65%). Therefore, HM training is an important component of RO residency, yet a minority of surveyed trainees felt quite or extremely well prepared to treat HM patients. Programs should explore alternative and additional educational opportunities to increase resident comfort with treating HM patients.

Impact of pathologic lymph node-positive renal cell carcinoma on survival in patients without metastasis: Evidence in support of expanding the definition of stage IV kidney cancer.

BACKGROUND: Stage III renal cell carcinoma (RCC) encompasses both lymph node-positive (pT1-3N1M0) and lymph node-negative (pT3N0M0) disease. However, prior institutional studies have indicated that among patients with stage III disease, those with lymph node disease have worse oncologic outcomes and experience survival that is similar to that of patients with American Joint Committee on Cancer (AJCC) stage IV disease. The objective of the current study was to validate these findings using a large, nationally representative sample of patients with kidney cancer. METHODS: Patients with AJCC stage III or stage IV RCC were identified using the National Cancer Data Base (NCDB). Patients were categorized as having lymph node-positive stage III (pT1-3N1M0), lymph node-negative stage III (pT3N0M0), or stage IV metastatic (pT1-3 N0M1) disease. Cox proportional hazards models compared outcomes while adjusting for comorbidities. Kaplan-Meier estimates illustrated relative survival when comparing staging groups. RESULTS: A total of 8988 patients met the inclusion criteria, with 6587 patients classified as having lymph node-negative stage III disease, 2218 as having lymph node-positive stage III disease, and 183 as having stage IV disease. Superior survival was noted among patients with lymph node-negative stage III disease, but similar survival was noted between patients with lymph node-positive stage III and stage IV RCC, with 5-year survival rates of 61.9% (95% confidence interval [95% CI], 60.3%-63.4%), 22.7% (95% CI, 20.6%-24.9%), and 15.6% (95% CI, 11.1%-23.8%), respectively. CONCLUSIONS: Current RCC staging systems group pT1-3N1M0 and pT3N0M0 disease as stage III disease. However, the results of the current validation study suggest the need for further stratification and even placement of patients with pT1-3N1M0 disease into the stage IV category. Staging that accurately reflects oncologic prognosis may help clinicians better counsel and select patients who might derive the most benefit from lymphadenectomy, adjuvant systemic therapy, more rigorous imaging surveillance, and clinical trial participation.

Reversal of the Warburg phenomenon in chemoprevention of prostate cancer by sulforaphane.

Inhibition of metabolic re-programming represents an attractive approach for prevention of prostate cancer. Studies have implicated increased synthesis of fatty acids or glycolysis in pathogenesis of human prostate cancers. We have shown previously that prostate cancer prevention by sulforaphane (SFN) in Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model is associated with inhibition of fatty acid metabolism. This study utilized human prostate cancer cell lines (LNCaP, 22Rv1 and PC-3), two different transgenic mouse models (TRAMP and Hi-Myc) and plasma specimens from a clinical study to explore the glycolysis inhibition potential of SFN. We found that SFN treatment: (i) decreased real-time extracellular acidification rate in LNCaP, but not in PC-3 cell line; (ii) significantly downregulated expression of hexokinase II (HKII), pyruvate kinase M2 and/or lactate dehydrogenase A (LDHA) in vitro in cells and in vivo in neoplastic lesions in the prostate of TRAMP and Hi-Myc mice; and (iii) significantly suppressed glycolysis in prostate of Hi-Myc mice as measured by ex vivo1H magnetic resonance spectroscopy. SFN treatment did not decrease glucose uptake or expression of glucose transporters in cells. Overexpression of c-Myc, but not constitutively active Akt, conferred protection against SFN-mediated downregulation of HKII and LDHA protein expression and suppression of lactate levels. Examination of plasma lactate levels in prostate cancer patients following administration of an SFN-rich broccoli sprout extract failed to show declines in its levels. Additional clinical trials are needed to determine whether SFN treatment can decrease lactate production in human prostate tumors.

A phase 2, randomized trial evaluating the combination of dalantercept plus axitinib in patients with advanced clear cell renal cell carcinoma.

BACKGROUND: In a prior open-label study, the combination of dalantercept, a novel antiangiogenic targeting activin receptor-like kinase 1 (ALK1), plus axitinib was deemed safe and tolerable with a promising efficacy signal in patients with advanced renal cell carcinoma (RCC). METHODS: In the current phase 2, randomized, double-blind, placebo-controlled study, patients with clear cell RCC previously treated with 1 prior angiogenesis inhibitor were randomized 1:1 to receive axitinib plus dalantercept versus axitinib plus placebo. Randomization was stratified by the type of prior therapy. The primary endpoint was progression-free survival (PFS). Secondary endpoints were PFS in patients with ≥2 prior lines of anticancer therapy, overall survival, and the objective response rate. RESULTS: Between June 10, 2014, and February 23, 2017, a total of 124 patients were randomly assigned to receive axitinib plus dalantercept (59 patients) or placebo (65 patients). The median PFS was not found to be significantly different between the treatment groups (median, 6.8 months vs 5.6 months; hazard ratio, 1.11 [95% CI, 0.71-1.73; P = .670]). Neither group reached the median overall survival (hazard ratio, 1.39 [95% CI, 0.70-2.77; P = .349]). The objective response rate was 19.0% (11 of 58 patients; 95% CI, 9.9%-31.4%) in the dalantercept plus axitinib group and 24.6% (15 of 61 patients; 95% CI, 14.5%-37.3%) in the placebo plus axitinib group. At least 1 treatment-emergent adverse event of ≥grade 3 was observed in 59% of patients (34 of 58 patients) in the dalantercept group and 64% of patients (39 of 61 patients) in the placebo group. One treatment-related death occurred in the placebo plus axitinib group. CONCLUSIONS: Although well tolerated, the addition of dalantercept to axitinib did not appear to improve treatment-related outcomes in previously treated patients with advanced RCC.

Automatic measurement of air gap for proton therapy using orthogonal x-ray imaging with radiopaque wires.

PURPOSE: The main objective of this study was to develop a technique to accurately determine the air gap between the end of the proton beam compensator and the body of the patient in proton radiotherapy. METHODS: Orthogonal x-ray image-based automatic coordinate reconstruction was used to determine the air gap between the patient body surface contour and the end of beam nozzle in proton radiotherapy. To be able to clearly identify the patient body surface contour on the orthogonal images, a radiopaque wire was placed on the skin surface of the patient as a surrogate. In order to validate this method, a Rando® head phantom was scanned and five proton plans were generated on a Mevion S250 Proton machine with various air gaps in Varian Eclipse Treatment Planning Systems (TPS). When setting up the phantom in a treatment room, a solder wire was placed on the surface of the phantom closest to the beam nozzle with the knowledge of the beam geometry in the plan. After the phantom positioning was verified using orthogonal kV imaging, the last pair of setup kV images was used to segment the solder wire and the in-room coordinates of the wire were reconstructed using a back-projection algorithm. Using the wire as a surrogate of the body surface, we calculated the air gaps by finding the minimum distance between the reconstructed wire and the end of the compensator. The methodology was also verified and validated on clinical cases. RESULTS: On the phantom study, the air gap values derived with the automatic reconstruction method were found to be within 1.1 mm difference from the planned values for proton beams with air gaps of 85.0, 100.0, 150.0, 180.0, and 200.0 mm. The reconstruction technique determined air gaps for a patient in two clinical treatment sessions were 38.4 and 41.8 mm, respectively, for a 40 mm planned air gap, and confirmed by manual measurements. There was strong agreement between the calculated values and the automatically measured values, and between the automatically and manually measured values. CONCLUSIONS: An image-based automatic method has been developed to conveniently determine the air gap of a proton beam, directly using the orthogonal images for patient positioning without adding additional imaging dose to the patient. The method provides an objective, accurate, and efficient way to confirm the target depth at treatment to ensure desired target coverage and normal tissue sparing.

A prolonged response to platinum-based therapy in a patient with metastatic urothelial carcinoma harboring a single rearranged and truncated NF2 gene.

Tumor genome sequencing has become an invaluable resource in determining targets for new therapies. In this report, we describe the case of a patient with metastatic urothelial carcinoma with sarcomatoid features. Sarcomatoid differentiation is a rare histologic subtype that confers a more aggressive course. The first-line treatment for patients with urothelial carcinoma is platinum-based chemotherapy. Next generation tumor sequencing performed using the FoundationOne assay revealed loss of one NF2 allele and an unbalanced der(22)t(10;22)(p11.22;q12.2) chromosomal rearrangement involving the other NF2 allele, resulting in truncation and predicted loss of function. Fluorescence in situ hybridization (FISH) analysis confirmed the presence of one NF2 signal. NF2 mutations have been found in a variety of cancers and result in activation of the mTOR pathway. As such, the use of mTOR inhibitors, such as everolimus are thought to be particularly effective in the case of NF2 loss. Our patient had a dramatic response to first-line chemotherapy, but unfortunately experienced subsequent progression of his cancer and could not tolerate everolimus. Although our patient's tumor demonstrated unique acquired genetic features including both loss of heterozygosity and truncation of the NF2 locus, he still achieved a meaningful response to platinum-based chemotherapy.

Using gEUD based plan analysis method to evaluate proton vs. photon plans for lung cancer radiation therapy.

The goal of this study was to exam the efficacy of current DVH based clinical guidelines draw from photon experience for lung cancer radiation therapy on proton therapy. Comparison proton plans and IMRT plans were generated for 10 lung patients treated in our proton facility. A gEUD based plan evaluation method was developed for plan evaluation. This evaluation method used normal lung gEUD(a) curve in which the model parameter "a" was sampled from the literature reported value. For all patients, the proton plans delivered lower normal lung V5 Gy with similar V20 Gy and similar target coverage. Based on current clinical guidelines, proton plans were ranked superior to IMRT plans for all 10 patients. However, the proton and IMRT normal lung gEUD(a) curves crossed for 8 patients within the tested range of "a", which means there was a possibility that proton plan would be worse than IMRT plan for lung sparing. A concept of deficiency index (DI) was introduced to quantify the probability of proton plans doing worse than IMRT plans. By applying threshold on DI, four patients' proton plan was ranked inferior to the IMRT plan. Meanwhile if a threshold to the location of curve crossing was applied, 6 patients' proton plan was ranked inferior to the IMRT plan. The contradictory ranking results between the current clinical guidelines and the gEUD(a) curve analysis demonstrated there is potential pitfalls by applying photon experience directly to the proton world. A comprehensive plan evaluation based on radio-biological models should be carried out to decide if a lung patient would really be benefit from proton therapy.

Local Therapy Improves Overall Survival in Patients With Newly Diagnosed Metastatic Prostate Cancer.

BACKGROUND: The role of local therapy, in the form of radiation therapy (RT) or radical prostatectomy(RP), and its association on outcomes is not well established in patients with metastatic prostate cancer. METHODS: Using the National Cancer Database (NCDB), we evaluated patterns of care and outcomes among patients diagnosed with metastatic prostate cancer from 2004 to 2013 treated with local therapy (RP, intensity-modulated radiation therapy [IMRT], or 2D/3D-conformal radiation therapy [CRT]). The association between local therapy, co-variates, and outcomes was assessed in a multivariable Cox proportional hazards model and Propensity score (PS) matching was performed to balance confounding factors. Survival was estimated using the Kaplan-Meier method. RESULTS: Among the 1,208,180 patients in the NCDB with prostate cancer, 6,051 patients met the inclusion criteria. No local therapy was used in 5,224 patients, while 622 (10.3%), 52 (0.9%), 153 (2.5%) patients received RP, IMRT, and 2D/3D-CRT, respectively. Use of local therapy was associated with younger age (≤70), lower co-morbidity score, lower T-stage, Gleason score <8, node-negative status, private, and Medicare insurance, higher income quartile, and treatment at comprehensive or academic/research programs (P < 0.05). Five-year overall survival for patients receiving local therapy was 45.7% versus 17.1% for those not receiving local therapy (P < 0.01). In multivariate analysis, RP (HR = 0.51; 95%CI, 0.45-0.59, P < 0.01) and IMRT (HR = 0.47; 95%CI, 0.31-0.72, P < 0.01) were independently associated with superior overall survival. After PS-matching, the use of local therapy (RP or IMRT) remained significantly associated with overall survival (HR = 0.35; 95%CI, 0.30-0.41, P < 0.01). CONCLUSIONS: The use of RP and IMRT, to treat the primary disease, was associated with improvements in overall survival for patients with metastatic prostate cancer. We have identified patient-specific variations in the use of local therapy that may be tested in subsequent prospective clinical trials to improve patient outcomes in this setting. Prostate 77: 559-572, 2017. © 2017 Wiley Periodicals, Inc.

Next-generation sequencing-based molecular characterization of primary urinary bladder adenocarcinoma.

Primary bladder adenocarcinoma is a rare and aggressive tumor with poor clinical outcomes and no standard of care therapy. Molecular biology of this tumor is unknown due to the lack of comprehensive molecular profiling studies. The study aimed to identify genomic alterations of clinical and therapeutic significance using next-generation sequencing and compare genomic profile of primary bladder adenocarcinoma with that of high-grade urothelial carcinoma and colorectal adenocarcinoma. A cohort of 15 well-characterized primary bladder adenocarcinoma was subjected to targeted next-generation sequencing for the identification of mutations and copy-number changes in 51 cancer-related genes. Genomic profiles of 25 HGUCs and 25 colorectal adenocarcinomas using next-generation sequencing of 50 genes were compared with primary bladder adenocarcinoma. Genomic profiles were visualized using JavaScript library D3.js. A striking finding was the distinct lack of genomic alterations across the 51 genes assessed in mucinous subtype of primary bladder adenocarcinoma. Eleven of 15 primary bladder adenocarcinoma harbored at least one genomic alteration in TP53, KRAS, PIK3CA, CTNNB1, APC, TERT, FBXW7, IDH2 and RB1, many of which are novel findings and of potential therapeutic significance. CTNNB1 and APC mutations were restricted to enteric subtype only. While genomic alterations of primary bladder adenocarcinoma showed substantial overlap with colorectal adenocarcinoma, FGFR3 and HRAS mutations and APC, CTNNB1 and IDH2 alterations were mutually exclusive between primary bladder adenocarcinoma and high-grade urothelial carcinoma. These alterations affecting the MAP kinase, PI3K/Akt, Wnt, IDH (metabolic) and Tp53/Rb1 signaling pathways may provide the opportunity for defining targeted therapeutic approaches.

Optimal Therapy for Early-Stage Hodgkin's Lymphoma: Risk Adapting, Response Adapting, and Role of Radiotherapy.

PURPOSE OF REVIEW: The aim of this article is to discuss the current role of radiotherapy (RT) for early-stage Hodgkin's lymphoma (HL) in the context of risk-adapted and response-adapted treatment strategy, and describe changes in RT technical approach. RECENT FINDINGS: In low-risk patients, RT could be omitted but, at the price of a lower progression-free survival, and its role is still debated. Ongoing trials are combining new agents with chemotherapy alone or response-adapted combined modality therapy, and results are awaited. Modern RT incorporates lower doses and smaller fields, together with the implementation of sophisticated delivery techniques aimed to reducing the dose to critical structures such as the heart. The role of RT for early-stage HL is still under debate, and new combinations are emerging; an individualized approach should be recommended, considering all RT technical opportunities to minimize toxicity while maintaining efficacy.

Disparities in receipt of modern concurrent chemoradiotherapy in glioblastoma.

Temozolomide given concurrently with radiation after resection/biopsy improves survival in glioblastoma (GBM). The disparities in receipt of adjuvant single-agent chemotherapy and their association with outcome have not been well established. Observational study of a prospectively collected database, the National Cancer Database (NCDB), from 1998 to 2012 with median follow-up 12.4 months. Among the 114,979 patients in the NCDB with GBM, 44,531 patients were analyzed for disparities, and 28,279 patients were analyzed for overall survival (OS). Associations were assessed in a multivariable Cox proportional hazards regression model. Survival was estimated using the Kaplan-Meier method. Median age was 58 years. Chemotherapy use was associated with male gender, white race, younger age (≤50), higher performance status (≥70), more extensive surgery, insurance status, higher income/education, and treatment at academic centers (all p < 0.05). We found improved OS associated with type of insurance (private insurance HR 0.91, 95 % CI 0.85-0.96 and Medicare HR 1.24, 95 % CI 1.16-1.33, both p < 0.01 compared to uninsured) and treatment at academic programs (HR 0.86; p < 0.01). MGMT methylation status predicted improved OS (HR 0.54; 95 % CI 0.41-0.70, p < 0.01). 1-year OS for patients receiving chemotherapy was 55.9 % versus 35.3 % for those without (p < 0.0001). After adjustment for confounders, chemotherapy use remained associated with improved OS (HR 0.64, 95 % CI 0.63-0.66, p < 0.01). Chemotherapy utilization increased from 26.9 to 93.3 % during the study period. We have identified specific disparities in the use of chemotherapy that may be targeted to improve patient access to care. Widespread adoption of adjuvant chemoradiotherapy after resection or biopsy for GBM appears to improve OS.

Disparities in survival by insurance status in patients with Hodgkin lymphoma.

BACKGROUND: The association between insurance status and outcomes has not been well established for patients with Hodgkin lymphoma (HL). The purpose of this study was to examine the disparities in overall survival (OS) by insurance status in a large cohort of patients with HL. METHODS: The National Cancer Data Base (NCDB) was used to evaluate patients with stage I to IV HL from 1998 to 2011. The association between insurance status, covariables, and outcomes was assessed in a multivariate Cox proportional hazards model. Survival was estimated with the Kaplan-Meier method. RESULTS: Among the 76,681 patients within the NCDB, 45,777 patients with stage I to IV HL were eligible for this study (median follow-up, 6.0 years). The median age was 39 years (range, 18-90 years). The insurance status was as follows: 3247 (7.1%) were uninsured, 7962 (17.4%) had Medicaid, 30,334 (66.3%) had private insurance, 3746 (8.2%) had managed care, and 488 (1.1%) had Medicare. Patients with an unfavorable insurance status (Medicaid/uninsured) were at a more advanced stage, had higher comorbidity scores, had B symptoms, and were in a lower income/education quartile (all P < .01). These patients were less likely to receive radiotherapy and start chemotherapy promptly and were less commonly treated at academic/research centers (all P < .01). Patients with unfavorable insurance had a 5-year OS of 54% versus 87% for those favorably insured (P < .01). When adjustments were made for covariates, an unfavorable insurance status was associated with significantly decreased OS (hazard ratio, 1.60; 95% confidence interval, 1.34-1.91; P < .01). The unfavorable insurance status rate increased from 22.8% to 28.8% between 1998 and 2011. CONCLUSIONS: This study reveals that HL patients with Medicaid and uninsured patients have outcomes inferior to those of patients with more favorable insurance. Targeting this subset of patients with limited access to care may help to improve outcomes. Cancer 2015;121:3435-43. © 2015 American Cancer Society.

5α-Reductase inhibition coupled with short off cycles increases survival in the LNCaP xenograft prostate tumor model on intermittent androgen deprivation therapy.

PURPOSE: Intermittent androgen deprivation therapy in patients with prostate specific antigen progression after localized prostate cancer treatment is an alternative to standard continuous androgen deprivation therapy. Intermittent androgen deprivation therapy allows for testosterone recovery during off cycles. This stimulates regrowth and differentiation of the regressed prostate tumor, lessens the side effects of continuous androgen deprivation therapy and potentially prolongs survival. Previously intermittent androgen deprivation therapy coupled with finasteride was shown to prolong survival in animals bearing androgen sensitive prostate tumors when the off cycle duration was not prolonged but rather fixed at 10 to 14 days. Regressed prostate tumor xenografts with testosterone replacement were initially responsive to 5α-reductase inhibition but growth resumed after several days. In shorter off cycles of testosterone recovery 5α-reductase inhibition might maximize tumor growth inhibition during intermittent androgen deprivation therapy and perhaps increase survival. MATERIALS AND METHODS: We used the LNCaP xenograft tumor model to evaluate the effectiveness of short off cycles of 4 days coupled with 5α-reductase inhibition on survival and tumor regrowth while on intermittent androgen deprivation therapy. RESULTS: Dutasteride inhibited initial testosterone induced tumor regrowth off cycles 1 and 2, and significantly increased survival. CONCLUSIONS: These results further support the potential for intermittent androgen deprivation therapy combined with 5α-reductase inhibition to improve survival in patients with prostate cancer when off cycle duration is short or very short.

Targeted inhibition of ATR or CHEK1 reverses radioresistance in oral squamous cell carcinoma cells with distal chromosome arm 11q loss.

Oral squamous cell carcinoma (OSCC), a subset of head and neck squamous cell carcinoma (HNSCC), is the eighth most common cancer in the U.S.. Amplification of chromosomal band 11q13 and its association with poor prognosis has been well established in OSCC. The first step in the breakage-fusion-bridge (BFB) cycle leading to 11q13 amplification involves breakage and loss of distal 11q. Distal 11q loss marked by copy number loss of the ATM gene is observed in 25% of all Cancer Genome Atlas (TCGA) tumors, including 48% of HNSCC. We showed previously that copy number loss of distal 11q is associated with decreased sensitivity (increased resistance) to ionizing radiation (IR) in OSCC cell lines. We hypothesized that this radioresistance phenotype associated with ATM copy number loss results from upregulation of the compensatory ATR-CHEK1 pathway, and that knocking down the ATR-CHEK1 pathway increases the sensitivity to IR of OSCC cells with distal 11q loss. Clonogenic survival assays confirmed the association between reduced sensitivity to IR in OSCC cell lines and distal 11q loss. Gene and protein expression studies revealed upregulation of the ATR-CHEK1 pathway and flow cytometry showed G2 M checkpoint arrest after IR treatment of cell lines with distal 11q loss. Targeted knockdown of the ATR-CHEK1 pathway using CHEK1 or ATR siRNA or a CHEK1 small molecule inhibitor (SMI, PF-00477736) resulted in increased sensitivity of the tumor cells to IR. Our results suggest that distal 11q loss is a useful biomarker in OSCC for radioresistance that can be reversed by ATR-CHEK1 pathway inhibition.

Upregulation of the ATR-CHEK1 pathway in oral squamous cell carcinomas.

The ATR-CHEK1 pathway is upregulated and overactivated in Ataxia Telangiectasia (AT) cells, which lack functional ATM protein. Loss of ATM in AT confers radiosensitivity, although ATR-CHEK1 pathway overactivation compensates, leads to prolonged G(2) arrest after treatment with ionizing radiation (IR), and partially reverses the radiosensitivity. We observed similar upregulation of the ATR-CHEK1 pathway in a subset of oral squamous cell carcinoma (OSCC) cell lines with ATM loss. In the present study, we report copy number gain, amplification, or translocation of the ATR gene in 8 of 20 OSCC cell lines by FISH; whereas the CHEK1 gene showed copy number loss in 12 of 20 cell lines by FISH. Quantitative PCR showed overexpression of both ATR and CHEK1 in 7 of 11 representative OSCC cell lines. Inhibition of ATR or CHEK1 with their respective siRNAs resulted in increased sensitivity of OSCC cell lines to IR by the colony survival assay. siRNA-mediated ATR or CHEK1 knockdown led to loss of G(2) cell cycle accumulation and an increased sub-G(0) apoptotic cell population by flow cytometric analysis. In conclusion, the ATR-CHEK1 pathway is upregulated in a subset of OSCC with distal 11q loss and loss of the G(1) phase cell cycle checkpoint. The upregulated ATR-CHEK1 pathway appears to protect OSCC cells from mitotic catastrophe by enhancing the G(2) checkpoint. Knockdown of ATR and/or CHEK1 increases the sensitivity of OSCC cells to IR. These findings suggest that inhibition of the upregulated ATR-CHEK1 pathway may enhance the efficacy of ionizing radiation treatment of OSCC.

Prognosis of South Asian Buccal Mucosa Cancer Patients in the United States: Association of Race with Overall Survival.

BACKGROUND: Squamous Cell Carcinoma (SCC) of the buccal mucosa and gingiva accounts for approximately 10% of oral and pharyngeal cancers diagnosed in the United States each year, with a disproportionally higher incidence in individuals of South Asian descent. However, little has been documented regarding trends pertaining to overall survival. Thus, this research serves to identify predictors of survival and determine if overall survival (OS) differs for South Asians compared to other races once they develop non-metastatic buccal mucosa or gingiva squamous cell carcinoma. METHODS: A population-based, cohort study of patients registered in the National Cancer Database® (NCDB) between the years 2004-2016 was performed. Kaplan-Meyer Survival Curves were executed to examine overall survival, while univariable (UVA) and multivariable analysis (MVA) was performed to determine the effect of multiple variables on OS. RESULTS: South Asians had longer median OS at 88.7 months, compared to 58.6 months and 38.3 months for Caucasians and African Americans respectively (p<0.001). In UVA, race was highly significant, but when the cohort was selected to include only those who had undergone surgical resection, no statistically significant difference remained. On MVA, lack of surgery, older age, higher grade, higher T and N stage, use of chemotherapy, higher comorbidity scores were associated with worse OS, but race was not significant. CONCLUSION: South Asians in the US with non-metastatic buccal mucosa or gingiva SCC have better OS compared to Caucasians or African Americans, likely due to younger age at diagnosis (median 59 vs. 71 and 62 years old) and more frequent surgical resection (75% vs. 72% and 64%). In MVA, South Asians have similar OS as Caucasians.