Patient attendance at molecular tumor board: A new means of shared decision making?

Patient engagement in medical decision-making improves patient related outcomes through compliance and patient satisfaction. The Inova Schar Cancer Institute has a weekly molecular tumor board (MTB) to match comprehensive genomic sequencing results with targeted therapies for patients. Primary oncologists extended MTB invitations to their patients. Ultimately, 20 of the 139 patients attended and completed pre- and post MTB surveys. There was a statistically significant change from the pre- to post- survey for the question "I am satisfied with how well informed I am about targeted therapy" with P = 0.016. Patients who attended MTB reported higher levels of satisfaction with their knowledge of targeted therapy after MTB as compared to before. A more holistic method of studying this practice would include sampling a larger patient population and a formal evaluation of the physicians' experience with patients attending.

A Rare Variant in ERF (rs144812092) Predisposes to Prostate and Bladder Cancers in an Extended Pedigree.

Pairs of related bladder cancer cases who belong to pedigrees with an excess of bladder cancer were sequenced to identify rare, shared variants as candidate predisposition variants. Candidate variants were tested for association with bladder cancer risk. A validated variant was assayed for segregation to other related cancer cases, and the predicted protein structure of this variant was analyzed. This study of affected bladder cancer relative pairs from high-risk pedigrees identified 152 bladder cancer predisposition candidate variants. One variant in ERF (ETS Repressing Factor) was significantly associated with bladder cancer risk in an independent population, was observed to segregate with bladder and prostate cancer in relatives, and showed evidence for altering the function of the associated protein. This finding of a rare variant in ERF that is strongly associated with bladder and prostate cancer risk in an extended pedigree both validates ERF as a cancer predisposition gene and shows the continuing value of analyzing affected members of high-risk pedigrees to identify and validate rare cancer predisposition variants.

TAp73 expression and P1 promoter methylation, a potential marker for chemoresponsiveness to cisplatin therapy and survival in muscle-invasive bladder cancer (MIBC).

Intrinsic and/or acquired resistance to cisplatin is a significant obstacle in the treatment of muscle-invasive bladder cancer. p73, a p53 homolog and determinant of chemosensitivity, is rarely mutated in bladder cancer (BC). However p73 expression and therefore function can be repressed through epigenetic changes. In this study, we sought to identify DNA methylation status of p73, expression of TAp73 isoform, and their role in cisplatin sensitivity in BC. Primary tumor samples from 338 bladder cancer patients showed decreased TAp73 expression in MIBC compared to superficial BC. Low TAp73 protein expression was associated with shorter overall survival. To investigate if the loss of expression was methylation dependent, we utilized Illumina 450K methylation arrays to interrogate over 150 BC patient samples. We found 12 distinct CpGs in the p73 gene locus that were hypermethylated in tumors compared to adjacent normal tissues. Patients with high p73 promoter methylation specifically at CpG site cg07382920 had worse survival. In vitro, treatment with a DNA demethylating agent, decitabine (DAC), decreased TAp73 methylation and upregulated expression in both CR-T24 (cisplatin resistant T24 cells) and wild type T24 cells. Furthermore, treatment with DAC increased cisplatin response in wild type T24 and CR-T24. Our studies indicate that TAp73 expression and P1 promoter methylation, specifically at the cg073892920 site, may have prognostic and diagnostic value in MIBC. In the setting of P1 promoter hypermethylation, DAC could be used as a potentiating agent of cisplatin-based chemotherapy.

Vitamin D3 enhances the response to cisplatin in bladder cancer through VDR and TAp73 signaling crosstalk.

BACKGROUND: Vitamin D3 (VitD) deficiency is linked to increased incidence and worse survival in bladder cancer (BCa). In addition to cystectomy, patients are treated with cisplatin-based chemotherapy, however 30%-50% of patients do not benefit from this treatment. The effects of VitD deficiency on response to chemotherapy remain unknown. METHODS: To test effects of VitD supplementation on the response to cisplatin we analyzed patient serum VitD levels and correlated that with survival. In vivo, VitD deficient mice were treated with cisplatin, with or without pretreatment with the active VitD metabolite, 1,25 dihydroxyvitamin D3 (1,25D3 ). Lastly, using BCa cell lines, T24 and RT-112, the mechanism of action of 1,25D3 and cisplatin combination treatment was determined by apoptosis assays, as well as western blot and RT-PCR. RESULTS: In this study, we determined that low serum 25 hydroxyvitamin D3 (25D3 ) levels was significantly associated with worse response to cisplatin. Pretreating deficient mice with 1,25D3 , reduced tumor volume compared to cisplatin monotherapy. In vitro, 1,25D3 pretreatment increased the apoptotic response to cisplatin. 1,25D3 pretreatment increased expression of TAp73 and its pro-apoptotic targets, in a VDR dependent manner. VDR and its transcriptional targets were induced after 1,25D3 treatment and further increased after the combination of 1,25D3 and cisplatin in a TAp73 dependent manner. CONCLUSIONS: Our data suggest that VitD deficiency could be a biomarker for poor response to cisplatin, and pretreating with VitD can increase the apoptotic response to cisplatin through VDR and TAp73 signaling crosstalk.

Calcitriol and cancer therapy: A missed opportunity.

The vitamin D receptor is expressed in most tissues of the body - and the cancers that arise from those tissues. The vitamin D signaling pathway is active in those tissues and cancers. This is at least consistent with the hypothesis that perturbing this signaling may have a favorable effect on the genesis and growth of cancers. Epidemiologic data indicate that vitamin D signaling may be important in the initiation and outcome of a number of types of cancer. Many studies have shown that calcitriol (1,25 dihydroxycholecalciferol) and other vitamin D compounds have antiproliferative, pro-apoptotic, anti-cell migration and antiangiogenic activity in a number of preclinical studies in many different cancer types. Unfortunately, the assessment of the activity of calcitriol or other vitamin D analogues in the treatment of cancer, as single agents or in combination with other anticancer agents has been stymied by the failure to adhere to commonly accepted principles of drug development and clinical trials conduct.

Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort.

BACKGROUND: While numerous epidemiologic studies have found an association between higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower breast cancer risk, few have assessed this association for concentrations >40 ng/ml. OBJECTIVE: To investigate the relationship between 25(OH)D concentration and breast cancer risk across a broad range of 25(OH)D concentrations among women aged 55 years and older. METHODS: Analyses used pooled data from two randomized clinical trials (N = 1129, N = 2196) and a prospective cohort (N = 1713) to examine a broad range of 25(OH)D concentrations. The outcome was diagnosis of breast cancer during the observation periods (median: 4.0 years). Three analyses were conducted: 1) Incidence rates were compared according to 25(OH)D concentration from <20 to ≥60 ng/ml (<50 to ≥150 nmol/L), 2) Kaplan-Meier plots were developed and 3) multivariate Cox regression was used to examine the association between 25(OH)D and breast cancer risk using multiple 25(OH)D measurements. RESULTS: Within the pooled cohort (N = 5038), 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). Results were similar for the three analyses. First, comparing incidence rates, there was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 vs <20 ng/ml (Rate Ratio = 0.18, P = 0.006). Second, Kaplan-Meier curves for concentrations of <20, 20-39, 40-59 and ≥60 ng/ml were significantly different (P = 0.02), with the highest proportion breast cancer-free in the ≥60 ng/ml group (99.3%) and the lowest proportion breast cancer-free in the <20 ng/ml group (96.8%). The proportion with breast cancer was 78% lower for ≥60 vs <20 ng/ml (P = 0.02). Third, multivariate Cox regression revealed that women with 25(OH)D concentrations ≥60 ng/ml had an 80% lower risk of breast cancer than women with concentrations <20 ng/ml (HR = 0.20, P = 0.03), adjusting for age, BMI, smoking status, calcium supplement intake, and study of origin. CONCLUSIONS: Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk with concentrations ≥60 ng/ml being most protective.

Vitamin D in prostate cancer.

Signaling through the vitamin D receptor has been shown to be biologically active and important in a number of preclinical studies in prostate and other cancers. Epidemiologic data also indicate that vitamin D signaling may be important in the cause and prognosis of prostate and other cancers. These data indicate that perturbation of vitamin D signaling may be a target for the prevention and treatment of prostate cancer. Large studies of vitamin D supplementation will be required to determine whether these observations can be translated into prevention strategies. This paper reviews the available data in the use of vitamin D compounds in the treatment of prostate cancer. Clinical data are limited which support the use of vitamin D compounds in the management of men with prostate cancer. However, clinical trials guided by existing preclinical data are limited.

Vitamin D Receptor Signaling and Cancer.

The vitamin D receptor (VDR) binds the secosteroid hormone 1,25(OH)2D3 with high affinity and regulates gene programs that control a serum calcium levels, as well as cell proliferation and differentiation. A significant focus has been to exploit the VDR in cancer settings. Although preclinical studies have been strongly encouraging, to date clinical trials have delivered equivocal findings that have paused the clinical translation of these compounds. However, it is entirely possible that mining of genomic data will help to refine precisely what are the key anticancer actions of vitamin D compounds and where these can be used most effectively.

1,25D3 differentially suppresses bladder cancer cell migration and invasion through the induction of miR-101-3p.

Metastasis is the major cause of bladder cancer death. 1,25D3, the active metabolite of vitamin D, has shown anti-metastasis activity in several cancer model systems. However, the role of 1,25D3 in migration and invasion in bladder cancer is unknown. To investigate whether 1,25D3 affects migration and invasion, four human bladder cell lines with different reported invasiveness were selected: low-invasive T24 and 253J cells and highly invasive 253J-BV and TCCSUP cells. All of the four bladder cancer cells express endogenous and inducible vitamin D receptor (VDR) as examined by immunoblot analysis. 1,25D3 had no effect on the proliferation of bladder cancer cells as assessed by MTT assay. In contrast, 1,25D3 suppressed migration and invasion in the more invasive 253J-BV and TCCSUP cells, but not in the low-invasive 253J and T24 cells using "wound" healing, chemotactic migration and Matrigel-based invasion assays. 1,25D3 promoted the expression of miR-101-3p and miR-126-3p in 253J-BV cells as examined by qRT-PCR. miR-101-3p inhibitor partially abrogated and pre-miR-101-3p further suppressed the inhibition of 1,25D3 on migration and invasion in 253J-BV cells. Further, 1,25D3 enhanced VDR recruitment to the promoter region of miR-101-3p using ChIP-qPCR assay. 1,25D3 enhanced the promoter activity of miR-101-3p as evaluated by luciferase reporter assay. Taken together, 1,25D3 suppresses bladder cancer cell migration and invasion in two invasive/migration competent lines but not in two less invasive/motile lines, which is partially through the induction of miR-101-3p expression at the transcriptional level.

Targeted therapies in the treatment of urothelial cancers.

Progress has been slow in systemic management of locally advanced and metastatic bladder cancer over the past 20 years. However, the recent approval of immunotherapy with atezolizumab and nivolumab for second-line salvage therapy may usher in an era of more rapid improvement. Systemic treatment is suboptimal and is an area of substantial unmet medical need. The recent findings from The Cancer Genome Atlas project revealed promising pathways that may be amenable to targeted therapies. Promising results with treatment using vascular endothelial growth factor inhibitors such as ramucirumab, sunitinib or bevacizumab, and human epidermal growth factor receptor 2 targeted therapies, epidermal growth factor receptor inhibitors, and fibroblast growth factor receptor inhibitors, are undergoing clinical trials and are discussed later.

Impact of suboptimal neoadjuvant chemotherapy on peri-operative outcomes and survival after robot-assisted radical cystectomy: a multicentre multinational study.

OBJECTIVES: To evaluate the effect of suboptimal dosing on the outcomes of patients who received neoadjuvant chemotherapy (NAC) and robot-assisted radical cystectomy (RARC). PATIENTS AND METHODS: We retrospectively reviewed 336 consecutive patients with urothelial carcinoma of the bladder who were treated with NAC and RARC at three academic institutions. Outcomes were compared among three groups: patients who received optimal NAC; patients who received suboptimal NAC; and those who did not receive NAC. To adjust for potential baseline differences between the three groups, propensity-score-based matching was performed. The suboptimal dose group was defined as those who received <3 cycles of cisplatin-based chemotherapy, received a decreased dosage, or those not treated with cisplatin. Primary outcomes analysed were recurrence-free survival (RFS) and overall survival (OS). Secondary outcomes were peri-operative complications and readmissions after RARC. RESULTS: After propensity-score matching, 69 patients in the cohort received optimal-dose NAC, 41 received suboptimal NAC and 69 did not receive NAC. Complication rates and readmission rates did not differ significantly among the three groups. On multivariable analysis, suboptimal NAC and no NAC were independent predictors of worse RFS (hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.2-5.7, P = 0.01 and HR 2.4, 95% CI 1.28-5.16, P = 0.01) and worse OS (HR 4.5, 95% CI 1.6-15.0, P < 0.01 and HR 4.9, 95% CI 1.9-15.6, P < 0.01) in patients who received NAC and RARC. Failure to achieve pathological complete response (ypT0N0) was also an independent predictor of worse RFS (HR 6.6, 95% CI 1.3-20.9; P = 0.02) and OS (HR 4.9, 95% CI 1.8-15.3; P = 0.02). CONCLUSION: Optimal NAC resulted in a better RFS and OS when compared with suboptimal or no NAC. Suboptimal and no NAC were associated with worse OS and RFS. These findings will facilitate improved patient counseling and treatment selection.

Pitfalls of improperly procured adjacent non-neoplastic tissue for somatic mutation analysis using next-generation sequencing.

BACKGROUND: The rapid adoption of next-generation sequencing provides an efficient system for detecting somatic alterations in neoplasms. The detection of such alterations requires a matched non-neoplastic sample for adequate filtering of non-somatic events such as germline polymorphisms. Non-neoplastic tissue adjacent to the excised neoplasm is often used for this purpose as it is simultaneously collected and generally contains the same tissue type as the neoplasm. Following NGS analysis, we and others have frequently observed low-level somatic mutations in these non-neoplastic tissues, which may impose additional challenges to somatic mutation detection as it complicates germline variant filtering. METHODS: We hypothesized that the low-level somatic mutation observed in non-neoplastic tissues may be entirely or partially caused by inadvertent contamination by neoplastic cells during the surgical pathology gross assessment or tissue procurement process. To test this hypothesis, we applied a systematic protocol designed to collect multiple grossly non-neoplastic tissues using different methods surrounding each single neoplasm. The procedure was applied in two breast cancer lumpectomy specimens. In each case, all samples were first sequenced by whole-exome sequencing to identify somatic mutations in the neoplasm and determine their presence in the adjacent non-neoplastic tissues. We then generated ultra-deep coverage using targeted sequencing to assess the levels of contamination in non-neoplastic tissue samples collected under different conditions. RESULTS: Contamination levels in non-neoplastic tissues ranged up to 3.5 and 20.9 % respectively in the two cases tested, with consistent pattern correlated with the manner of grossing and procurement. By carefully controlling the conditions of various steps during this process, we were able to eliminate any detectable contamination in both patients. CONCLUSION: The results demonstrated that the process of tissue procurement contributes to the level of contamination in non-neoplastic tissue, and contamination can be reduced to below detectable levels by using a carefully designed collection method. A standard protocol dedicated for acquiring adjacent non-neoplastic tissue that minimizes neoplasm contamination should be implemented for all somatic mutation detection studies.

Systemic therapy in muscle-invasive and metastatic bladder cancer: current trends and future promises.

Bladder urothelial cancers remain an important urologic cancer with limited treatment options in the locally advanced and metastatic setting. While neoadjuvant chemotherapy for locally advanced muscle-invasive cancers has shown overall survival benefit, clinical uptake in practice have lagged behind. Controversies surrounding adjuvant chemotherapy use are also ongoing. Systemic therapies for metastatic bladder cancer have largely used platinum-based therapies without effective standard second-line therapy options for those who fail, although vinflunine is approved in Europe as a second-line therapy based on a Phase III trial, and most recently, atezolizumab, a checkpoint inhibitor, was approved by the US FDA. Given increasing recognition of mutational signatures expressed in urothelial carcinomas, several promising agents with use of VEGF-targeted therapies, HER2-directed agents and immunotherapies with PD-1/PD-L1 antibodies in various settings are discussed herein.

Mechanistic Insights of Vitamin D Anticancer Effects.

Vitamin D is a secosteroid hormone that regulates many biological functions in addition to its classical role in maintaining calcium homeostasis and bone metabolism. Vitamin D deficiency appears to predispose individuals to increased risk of developing a number of cancers. Compelling epidemiological and experimental evidence supports a role for vitamin D in cancer prevention and treatment in many types of cancers. Preclinical studies show that 1,25D3, the active metabolite of vitamin D, and its analogs have antitumor effects in vitro and in vivo through multiple mechanisms including the induction of cell cycle arrest, apoptosis, differentiation and the suppression of inflammation, angiogenesis, invasion, and metastasis. 1,25D3 also potentiates the effect of chemotherapeutic agents and other agents in the combination treatment. In this review, the antitumor effects of 1,25D3 and the potential underlying mechanisms will be discussed. The current findings support the application of 1,25D3 in cancer prevention and treatment.

Vitamin D Signaling Modulators in Cancer Therapy.

The antiproliferative and pro-apoptotic effects of 1α,25-dihydroxycholecalciferol (1,25(OH)2D3, 1,25D3, calcitriol) have been demonstrated in various tumor model systems in vitro and in vivo. However, limited antitumor effects of 1,25D3 have been observed in clinical trials. This may be attributed to a variety of factors including overexpression of the primary 1,25D3 degrading enzyme, CYP24A1, in tumors, which would lead to rapid local inactivation of 1,25D3. An alternative strategy for improving the antitumor activity of 1,25D3 involves the combination with a selective CYP24A1 inhibitor. The validity of this approach is supported by numerous preclinical investigations, which demonstrate that CYP24A1 inhibitors suppress 1,25D3 catabolism in tumor cells and increase the effects of 1,25D3 on gene expression and cell growth. Studies are now required to determine whether selective CYP24A1 inhibitors+1,25D3 can be used safely and effectively in patients. CYP24A1 inhibitors plus 1,25D3 can cause dose-limiting toxicity of vitamin D (hypercalcemia) in some patients. Dexamethasone significantly reduces 1,25D3-mediated hypercalcemia and enhances the antitumor activity of 1,25D3, increases VDR-ligand binding, and increases VDR protein expression. Efforts to dissect the mechanisms responsible for CYP24A1 overexpression and combinational effect of 1,25D3/dexamethasone in tumors are underway. Understanding the cross talk between vitamin D receptor (VDR) and glucocorticoid receptor (GR) signaling axes is of crucial importance to the design of new therapies that include 1,25D3 and dexamethasone. Insights gained from these studies are expected to yield novel strategies to improve the efficacy of 1,25D3 treatment.

Predictors of Complete Pathologic Response (pT0) to Neoadjuvant Chemotherapy in Muscle-invasive Bladder Carcinoma.

UNLABELLED: No predictors of a complete pathologic response (pT0) to neoadjuvant chemotherapy (NAC) in muscle-invasive bladder carcinoma have been established. We performed a retrospective analysis of 50 patients to identify potential predictors. Our results showed that the presence of additional transitional cell variants on pathologic examination (mixed tumors) predicted against pT0, suggesting the avoidance of NAC and its morbidity in these patients with mixed tumors. BACKGROUND: Randomized trials have supported the use of cisplatin-based neoadjuvant chemotherapy (NAC) in muscle-invasive bladder carcinoma (MIBC) owing to the survival advantage, which has correlated with downstaging of the cancer to pT0. Only 30% to 40% of patients receiving NAC have attained a pT0 response at cystectomy; the remaining have either residual disease or progression. We aimed to identify the factors that could predict a pT0 response to NAC. PATIENTS AND METHODS: Of 336 patients who had undergone robotic cystectomy at our institute from May 2007 to March 2014, we identified 50 patients who had undergone NAC for MIBC. We conducted a retrospective study, dividing these 50 patients into 2 groups, those with and without a pT0. Factors, including age, histologic features, hydronephrosis at initial presentation, and chemotherapy type, were examined by both univariate and multivariate logistic regression analysis. RESULTS: Of the 50 patients, 14 (28%) had pT0 at cystectomy, 20 (40%) had progressive disease, and 16 (32%) had residual disease. The median age was 67.5 years, the median glomerular filtration rate at presentation was 87.5 mL/min, the patients had undergone a median of 3 NAC cycles, and the median time from the end of chemotherapy to surgery was 4 weeks. The odds of a pT0 response for pure urothelial carcinoma (UC) were approximately 11 times greater relative to cancers with transitional cell variant histologic features or mixed tumors (odds ratio 0.09, 95% confidence interval 0.021-0.380; P = .0011), including squamous, glandular differentiation, small cell, micropapillary, sarcomatoid, nested component, lymphoepithelioma-like, and plasmacytoid variants. CONCLUSION: The presence of pure UC favored a pT0 response to NAC compared with those with variant histologic features or mixed tumors. These potential predictors warrant prospective validation to allow the ideal selection of patients for NAC.

Genetic variations in vitamin D-related pathways and breast cancer risk in African American women in the AMBER consortium.

Studies of genetic variations in vitamin D-related pathways and breast cancer risk have been conducted mostly in populations of European ancestry, and only sparsely in African Americans (AA), who are known for a high prevalence of vitamin D deficiency. We analyzed 24,445 germline variants in 63 genes from vitamin D-related pathways in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium, including 3,663 breast cancer cases and 4,687 controls. Odds ratios (OR) were derived from logistic regression models for overall breast cancer, by estrogen receptor (ER) status (1,983 ER positive and 1,098 ER negative), and for case-only analyses of ER status. None of the three vitamin D-related pathways were associated with breast cancer risk overall or by ER status. Gene-level analyses identified associations with risk for several genes at a nominal p ≤ 0.05, particularly for ER- breast cancer, including rs4647707 in DDB2. In case-only analyses, vitamin D metabolism and signaling pathways were associated with ER- cancer (pathway-level p = 0.02), driven by a single gene CASR (gene-level p = 0.001). The top SNP in CASR was rs112594756 (p = 7 × 10(-5), gene-wide corrected p = 0.01), followed by a second signal from a nearby SNP rs6799828 (p = 1 × 10(-4), corrected p = 0.03). In summary, several variants in vitamin D pathways were associated with breast cancer risk in AA women. In addition, CASR may be related to tumor ER status, supporting a role of vitamin D or calcium in modifying breast cancer phenotypes.

The Incidental Use of High-Dose Vitamin D3 in Pancreatic Cancer.

Background: Pancreatic adenocarcinoma is associated with a very poor prognosis, with a 5 year survival of ∼7.2%. Vitamin D has long been evaluated for benefit as a protective agent and treatment for malignancies. Although cancer incidence and outcomes have been tied to vitamin D levels, there is no clear evidence that supplementation of vitamin D improves outcome in pancreatic cancer to date. Case Presentation: We present a patient who errantly took supratherapeutic doses of vitamin D 50,000 U daily, achieving a serum 25(OH)D level of more than 150 mg/mL, with no appreciable side effects. Conclusion: Her disease was stable for 8 months off of conventional treatment, although it is unclear whether this was related to vitamin D supplementation.

Vitamin D Repletion Reduces the Progression of Premalignant Squamous Lesions in the NTCU Lung Squamous Cell Carcinoma Mouse Model.

The chemopreventive actions of vitamin D were examined in the N-nitroso-tris-chloroethylurea (NTCU) mouse model, a progressive model of lung squamous cell carcinoma (SCC). SWR/J mice were fed a deficient diet (D) containing no vitamin D3, a sufficient diet (S) containing 2,000 IU/kg vitamin D3, or the same diets in combination with the active metabolite of vitamin D, calcitriol (C; 80 µg/kg, weekly). The percentage (%) of the mucosal surface of large airways occupied by dysplastic lesions was determined in mice after treatment with a total dose of 15 or 25 µmol NTCU (N). After treatment with 15 µmol NTCU, the percentages of the surface of large airways containing high-grade dysplastic (HGD) lesions were vitamin D-deficient + NTCU (DN), 22.7% [P < 0.05 compared with vitamin D-sufficient +NTCU (SN)]; DN + C, 12.3%; SN, 8.7%; and SN + C, 6.6%. The extent of HGD increased with NTCU dose in the DN group. Proliferation, assessed by Ki-67 labeling, increased upon NTCU treatment. The highest Ki-67 labeling index was seen in the DN group. As compared with SN mice, DN mice exhibited a three-fold increase (P < 0.005) in circulating white blood cells (WBC), a 20% (P < 0.05) increase in IL6 levels, and a four-fold (P < 0.005) increase in WBC in bronchial lavages. Thus, vitamin D repletion reduces the progression of premalignant lesions, proliferation, and inflammation, and may thereby suppress development of lung SCC. Further investigations of the chemopreventive effects of vitamin D in lung SCC are warranted.