Targeting MYC-enhanced glycolysis for the treatment of small cell lung cancer.

INTRODUCTION: The transcription factor MYC is overexpressed in 30% of small cell lung cancer (SCLC) tumors and is known to modulate the balance between two major pathways of metabolism: glycolysis and mitochondrial respiration. This duality of MYC underscores the importance of further investigation into its role in SCLC metabolism and could lead to insights into metabolic targeting approaches. METHODS: We investigated differences in metabolic pathways in transcriptional and metabolomics datasets based on cMYC expression in patient and cell line samples. Metabolic pathway utilization was evaluated by flow cytometry and Seahorse extracellular flux methodology. Glycolysis inhibition was evaluated in vitro and in vivo using PFK158, a small molecular inhibitor of PFKFB3. RESULTS: MYC-overexpressing SCLC patient samples and cell lines exhibited increased glycolysis gene expression directly mediated by MYC. Further, MYC-overexpressing cell lines displayed enhanced glycolysis consistent with the Warburg effect, while cell lines with low MYC expression appeared more reliant on oxidative metabolism. Inhibition of glycolysis with PFK158 preferentially attenuated glucose uptake, ATP production, and lactate in MYC-overexpressing cell lines. Treatment with PFK158 in xenografts delayed tumor growth and decreased glycolysis gene expression. CONCLUSIONS: Our study highlights an in-depth characterization of SCLC metabolic programming and presents glycolysis as a targetable mechanism downstream of MYC that could offer therapeutic benefit in a subset of SCLC patients.

Characterization of the Immune Landscape of EGFR-Mutant NSCLC Identifies CD73/Adenosine Pathway as a Potential Therapeutic Target.

INTRODUCTION: Lung adenocarcinomas harboring EGFR mutations do not respond to immune checkpoint blockade therapy and their EGFR wildtype counterpart. The mechanisms underlying this lack of clinical response have been investigated but remain incompletely understood. METHODS: We analyzed three cohorts of resected lung adenocarcinomas (Profiling of Resistance Patterns of Oncogenic Signaling Pathways in Evaluation of Cancer of Thorax, Immune Genomic Profiling of NSCLC, and The Cancer Genome Atlas) and compared tumor immune microenvironment of EGFR-mutant tumors to EGFR wildtype tumors, to identify actionable regulators to target and potentially enhance the treatment response. RESULTS: EGFR-mutant NSCLC exhibited low programmed death-ligand 1, low tumor mutational burden, decreased number of cytotoxic T cells, and low T cell receptor clonality, consistent with an immune-inert phenotype, though T cell expansion ex vivo was preserved. In an analysis of 75 immune checkpoint genes, the top up-regulated genes in the EGFR-mutant tumors (NT5E and ADORA1) belonged to the CD73/adenosine pathway. Single-cell analysis revealed that the tumor cell population expressed CD73, both in the treatment-naive and resistant tumors. Using coculture systems with EGFR-mutant NSCLC cells, T regulatory cell proportion was decreased with CD73 knockdown. In an immune-competent mouse model of EGFR-mutant lung cancer, the CD73/adenosine pathway was markedly up-regulated and CD73 blockade significantly inhibited tumor growth. CONCLUSIONS: Our work revealed that EGFR-mutant NSCLC has an immune-inert phenotype. We identified the CD73/adenosine pathway as a potential therapeutic target for EGFR-mutant NSCLC.

AXL Inhibition Induces DNA Damage and Replication Stress in Non-Small Cell Lung Cancer Cells and Promotes Sensitivity to ATR Inhibitors.

AXL, a TAM (TYRO3, AXL, and MERTK) family receptor tyrosine kinase, is increasingly being recognized as a key determinant of resistance to targeted therapies, as well as chemotherapy and radiation in non-small cell lung cancer (NSCLC) and other cancers. We further show here that high levels of AXL and epithelial-to-mesenchymal transition were frequently expressed in subsets of both treatment-naïve and treatment-relapsed NSCLC. Previously, we and others have demonstrated a role for AXL in mediating DNA damage response (DDR), as well as resistance to inhibition of WEE1, a replication stress response kinase. Here, we show that BGB324 (bemcentinib), a selective small-molecule AXL inhibitor, caused DNA damage and induced replication stress, indicated by ATR/CHK1 phosphorylation, more significantly in TP53-deficient NSCLC cell lines. Similar effects were also observed in large-cell neuroendocrine carcinoma (LCNEC) cell lines. High AXL protein levels were also associated with resistance to ATR inhibition. Combined inhibition of AXL and ATR significantly decreased cell proliferation of NSCLC and LCNEC cell lines. Mechanistically, combined inhibition of AXL and ATR significantly increased RPA32 hyperphosphorylation and DNA double-strand breaks and induced markers of mitotic catastrophe. Notably, NSCLC cell lines with low levels of SLFN11, a known predictive biomarker for platinum and PARP inhibitor sensitivity, were more sensitive to AXL/ATR cotargeting. These findings demonstrate a novel and unexpected role for AXL in replication stress tolerance, with potential therapeutic implications. IMPLICATIONS: These findings demonstrate that the combination of AXL and ATR inhibitors could be a promising therapeutic combination for NSCLC, LCNEC, and other cancers.

Patterns of protein expression in human head and neck cancer cell lines differ after proton vs photon radiotherapy.

BACKGROUND: Proton radiotherapy (PRT) may be a less toxic alternative to photon radiotherapy (XRT) for patients with head and neck squamous cell carcinoma (HNSCC). However, the molecular responses of HNSCC cells to PRT vs XRT are unclear. METHODS: Proteomics analyses of protein expression profiles by reverse-phase protein arrays were done for two human papillomavirus [HPV]-negative and two HPV+ cell lines. Expression patterns of 175 proteins involved in several signaling pathways were tested. RESULTS: Compared with PRT, XRT tended to induce lower expression of DNA damage repair-and cell cycle arrest-related proteins and higher expression of cell survival- and proliferation-related proteins. CONCLUSIONS: Under these experimental conditions, PRT and XRT induced different protein expression and activation profiles. Further preclinical verification is needed, as are studies of tumor pathway mutations as biomarkers for choice of treatment or as radiosensitization targets to improve the response of HNSCC to PRT or XRT.

Met Receptor Tyrosine Kinase and Chemoprevention of Oral Cancer.

Background: We have previously shown that gene expression profiles of oral leukoplakia (OL) may improve the prediction of oral cancer (OC) risk. To identify new targets for prevention, we performed a systematic survey of transcripts associated with an increased risk of oral cancer and overexpressed in OC vs normal mucosa (NM). Methods: We used gene expression profiles of 86 patients with OL and available outcomes from a chemoprevention trial of OC and NM. MET expression was evaluated using immunohistochemistry in 120 OL patients, and its association with OC development was tested in multivariable analysis. Sensitivity to pharmacological Met inhibition was tested invitro in premalignant and OC cell lines (n = 33) and invivo using the 4-NQO model of oral chemoprevention (n = 20 mice per group). All statistical tests were two-sided. Results: The overlap of 693 transcripts associated with an increased risk of OC with 163 transcripts overexpressed in OC compared with NM led to the identification of 23 overlapping transcripts, including MET. MET overexpression in OL was associated with a hazard ratio of 3.84 (95% confidence interval = 1.59 to 9.27, P = .003) of developing OC. Met activation was found in OC and preneoplastic cell lines. Crizotinib activity in preneoplastic and OC cell lines was comparable. ARQ 197 was more active in preneoplastic compared with OC cell lines. In the 4-NQO model, squamous cell carcinoma, dysplasia, and hyperkeratosis were observed in 75.0%, 15.0%, and 10.0% in the control group, and in 25.0%, 70.0%, and 5.0% in the crizotinib group (P < .001). Conclusion: Together, these data suggest that MET activation may represent an early driver in oral premalignancy and a target for chemoprevention of OC.

Protein expression of TTF1 and cMYC define distinct molecular subgroups of small cell lung cancer with unique vulnerabilities to aurora kinase inhibition, DLL3 targeting, and other targeted therapies.

Small cell lung cancer (SCLC) is a recalcitrant cancer for which no new treatments have been approved in over 30 years. While molecular subtyping now guides treatment selection for patients with non-small cell lung cancer and other cancers, SCLC is still treated as a single disease entity. Using model-based clustering, we found two major proteomic subtypes of SCLC characterized by either high thyroid transcription factor-1 (TTF1)/low cMYC protein expression or high cMYC/low TTF1. Applying "drug target constellation" (DTECT) mapping, we further show that protein levels of TTF1 and cMYC predict response to targeted therapies including aurora kinase, Bcl2, and HSP90 inhibitors. Levels of TTF1 and DLL3 were also highly correlated in preclinical models and patient tumors. TTF1 (used in the diagnosis lung cancer) could therefore be used as a surrogate of DLL3 expression to identify patients who may respond to the DLL3 antibody-drug conjugate rovalpituzumab tesirine. These findings suggest that TTF1, cMYC or other protein markers identified here could be used to identify subgroups of SCLC patients who may respond preferentially to several emerging targeted therapies.

CHK1 Inhibition in Small-Cell Lung Cancer Produces Single-Agent Activity in Biomarker-Defined Disease Subsets and Combination Activity with Cisplatin or Olaparib.

Effective targeted therapies for small-cell lung cancer (SCLC), the most aggressive form of lung cancer, remain urgently needed. Here we report evidence of preclinical efficacy evoked by targeting the overexpressed cell-cycle checkpoint kinase CHK1 in SCLC. Our studies employed RNAi-mediated attenuation or pharmacologic blockade with the novel second-generation CHK1 inhibitor prexasertib (LY2606368), currently in clinical trials. In SCLC models in vitro and in vivo, LY2606368 exhibited strong single-agent efficacy, augmented the effects of cisplatin or the PARP inhibitor olaparib, and improved the response of platinum-resistant models. Proteomic analysis identified CHK1 and MYC as top predictive biomarkers of LY2606368 sensitivity, suggesting that CHK1 inhibition may be especially effective in SCLC with MYC amplification or MYC protein overexpression. Our findings provide a preclinical proof of concept supporting the initiation of a clinical efficacy trial in patients with platinum-sensitive or platinum-resistant relapsed SCLC. Cancer Res; 77(14); 3870-84. ©2017 AACR.

Integrative Analysis Identifies a Novel AXL-PI3 Kinase-PD-L1 Signaling Axis Associated with Radiation Resistance in Head and Neck Cancer.

Purpose: The primary cause of death due to head and neck squamous cell carcinoma (HNSCC) is local treatment failure. The goal of this study was to examine this phenomenon using an unbiased approach.Experimental Design: We utilized human papilloma virus (HPV)-negative cell lines rendered radiation-resistant (RR) via repeated exposure to radiation, a panel of HPV-negative HNSCC cell lines and three cohorts of HPV-negative HNSCC tumors (n = 68, 97, and 114) from patients treated with radiotherapy and subjected to genomic, transcriptomic, and proteomic analysis.Results: RR cell lines exhibited upregulation of several proteins compared with controls, including increased activation of Axl and PI3 kinase signaling as well as increased expression of PD-L1. Additionally, inhibition of either Axl or PI3 kinase led to decreased PD-L1 expression. When clinical samples were subjected to RPPA and mRNA expression analysis, PD-L1 was correlated with both Axl and PI3K signaling as well as dramatically associated with local failure following radiotherapy. This finding was confirmed examining a third cohort using immunohistochemistry. Indeed, tumors with high expression of PD-L1 had failure rates following radiotherapy of 60%, 70%, and 50% compared with 20%, 25%, and 20% in the PD-L1-low expression group (P = 0.01, 1.9 × 10-3, and 9 × 10-4, respectively). This finding remained significant on multivariate analysis in all groups. Additionally, patients with PD-L1 low/CD8+ tumor-infiltrating lymphocytes high had no local failure or death due to disease (P = 5 × 10-4 and P = 4 × 10-4, respectively).Conclusions: Taken together, our data point to a targetable Axl-PI3 kinase-PD-L1 axis that is highly associated with radiation resistance. Clin Cancer Res; 23(11); 2713-22. ©2017 AACR.

Proteomic Profiling Identifies PTK2/FAK as a Driver of Radioresistance in HPV-negative Head and Neck Cancer.

PURPOSE: Head and neck squamous cell carcinoma (HNSCC) is commonly treated with radiotherapy, and local failure after treatment remains the major cause of disease-related mortality. To date, human papillomavirus (HPV) is the only known clinically validated, targetable biomarkers of response to radiation in HNSCC. EXPERIMENTAL DESIGN: We performed proteomic and transcriptomic analysis of targetable biomarkers of radioresistance in HPV-negative HNSCC cell lines in vitro, and tested whether pharmacologic blockade of candidate biomarkers sensitized cells to radiotherapy. Candidate biomarkers were then investigated in several independent cohorts of patients with HNSCC. RESULTS: Increased expression of several targets was associated with radioresistance, including FGFR, ERK1, EGFR, and focal adhesion kinase (FAK), also known as PTK2. Chemical inhibition of PTK2/FAK, but not FGFR, led to significant radiosensitization with increased G2-M arrest and potentiated DNA damage. PTK2/FAK overexpression was associated with gene amplification in HPV-negative HNSCC cell lines and clinical tumors. In two independent cohorts of patients with locally advanced HPV-negative HNSCC, PTK2/FAK amplification was highly associated with poorer disease-free survival (DFS; P = 0.012 and 0.034). PTK2/FAK mRNA expression was also associated with worse DFS (P = 0.03). Moreover, both PTK2/FAK mRNA (P = 0.021) and copy number (P = 0.063) were associated with DFS in the Head and Neck Cancer subgroup of The Cancer Genome Atlas. CONCLUSIONS: Proteomic analysis identified PTK2/FAK overexpression is a biomarker of radioresistance in locally advanced HNSCC, and PTK2/FAK inhibition radiosensitized HNSCC cells. Combinations of PTK2/FAK inhibition with radiotherapy merit further evaluation as a therapeutic strategy for improving local control in HPV-negative HNSCC. Clin Cancer Res; 22(18); 4643-50. ©2016 AACR.

Epithelial-Mesenchymal Transition Is Associated with a Distinct Tumor Microenvironment Including Elevation of Inflammatory Signals and Multiple Immune Checkpoints in Lung Adenocarcinoma.

PURPOSE: Promising results in the treatment of non-small cell lung cancer (NSCLC) have been seen with agents targeting immune checkpoints, such as programmed cell death 1 (PD-1) or programmed death ligand-1 (PD-L1). However, only a select group of patients respond to these interventions. The identification of biomarkers that predict clinical benefit to immune checkpoint blockade is critical to successful clinical translation of these agents. METHODS: We conducted an integrated analysis of three independent large datasets, including The Cancer Genome Atlas of lung adenocarcinoma and two datasets from MD Anderson Cancer Center (Houston, TX), Profiling of Resistance Patterns and Oncogenic Signaling Pathways in Evaluation of Cancers of the Thorax (named PROSPECT) and Biomarker-Integrated Approaches of Targeted Therapy for Lung Cancer Elimination (named BATTLE-1). Comprehensive analysis of mRNA gene expression, reverse-phase protein array, IHC, and correlation with clinical data were performed. RESULTS: Epithelial-mesenchymal transition (EMT) is highly associated with an inflammatory tumor microenvironment in lung adenocarcinoma, independent of tumor mutational burden. We found immune activation coexistent with elevation of multiple targetable immune checkpoint molecules, including PD-L1, PD-L2, PD-1, TIM-3, B7-H3, BTLA, and CTLA-4, along with increases in tumor infiltration by CD4(+)Foxp3(+) regulatory T cells in lung adenocarcinomas that displayed an EMT phenotype. Furthermore, we identify B7-H3 as a prognostic marker for NSCLC. CONCLUSIONS: The strong association between EMT status and an inflammatory tumor microenvironment with elevation of multiple targetable immune checkpoint molecules warrants further investigation of using EMT as a predictive biomarker for immune checkpoint blockade agents and other immunotherapies in NSCLC and possibly a broad range of other cancers. Clin Cancer Res; 22(14); 3630-42. ©2016 AACRSee related commentary by Datar and Schalper, p. 3422.

8-Chloroadenosine Sensitivity in Renal Cell Carcinoma Is Associated with AMPK Activation and mTOR Pathway Inhibition.

The adenosine analog 8-chloroadenosine has been shown to deplete ATP and inhibit tumor growth in hematological malignancies as well as in lung and breast cancer cell lines. We investigated effects of 8-chloroadenosine on clear cell (cc) renal cell carcinoma (RCC) cell lines. 8-chloroadenosine was effective against ccRCC cell viability in vitro, with IC50 ranging from 2 µM in the most sensitive CAKI-1 to 36 µM in the most resistant RXF-393. Proteomic analysis by reverse-phase protein array revealed that 8-chloroadenosine treatment leads to inhibition of the mTOR pathway. In time-course experiments, 8-chloroadenosine treatment rapidly activated AMPK, measured by AMPK and ACC phosphorylation, and subsequently caused dephosphorylation of p70S6K and ribosomal protein RPS6 in the sensitive cell lines. However, in the resistant cell lines, AMPK activity and the mTOR pathway were unaffected by the treatment. We also noted that the resistant cell lines had elevated basal levels of phospho RPS6 and AKT. Inhibition of PI3K pathway enhanced the efficacy of 8-chloroadenosine across all cell lines. Our observations indicate that 8-chloroadenosine activity is associated with inhibition of the mTOR pathway, and that phospho RPS6 and PI3K pathway activation status may determine resistance. Among solid tumors, RCC is one of the few susceptible to mTOR inhibition. We thus infer that 8-chloroadenosine may be effective in RCC by activating AMPK and inhibiting the mTOR pathway.

A comprehensive evaluation of biomarkers predictive of response to PI3K inhibitors and of resistance mechanisms in head and neck squamous cell carcinoma.

The PI3K/AKT/mTOR pathway is frequently activated in head and neck squamous cell carcinoma (HNSCC), but pathway inhibition has variable efficacy. Identification of predictive biomarkers and mechanisms of resistance would allow selection of patients most likely to respond and novel therapeutic combinations. The purpose of this study was to extend recent discoveries regarding the PI3K/AKT/mTOR pathway in HNSCC by more broadly examining potential biomarkers of response, by examining pathway inhibitors with a diverse range of targets, and by defining mechanisms of resistance and potential combination therapies. We used reverse-phase protein arrays (RPPA) to simultaneously evaluate expression of 195 proteins; SNP array to estimate gene copy number; and mass array to identify mutations. We examined altered signaling at baseline and after pathway inhibition. Likewise, we examined the activation of the PI3K/AKT/mTOR pathway in HNSCC tumors by RPPA. Cell lines with PIK3CA mutations were sensitive to pathway inhibitors, whereas amplification status did not predict sensitivity. While we identified a set of individual candidate biomarkers of response to pathway inhibitors, proteomic pathway scores did not correlate with amplification or mutation and did not predict response. Several receptor tyrosine kinases, including EGFR and ERK, were activated following PI3K inhibition in resistant cells; dual pathway inhibition of PI3K and EGFR or MEK demonstrated synergy. Combined MEK and PI3K inhibition was markedly synergistic in HRAS-mutant cell lines. Our findings indicate that clinical trials of single-agent PI3K/AKT/mTOR pathway inhibitors in selected populations and of PI3K/EGFR or PI3K/MEK inhibitor combinations are warranted; we plan to conduct such trials.

Proteomic markers of DNA repair and PI3K pathway activation predict response to the PARP inhibitor BMN 673 in small cell lung cancer.

PURPOSE: Small cell lung carcinoma (SCLC) is an aggressive malignancy affecting nearly 30,000 people annually in the United States. We have previously identified elevated PARP1 levels in SCLC and demonstrated in vitro sensitivity to the PARP inhibitors AZD 2281 and AG014699. Here, we evaluate activity of a novel, potent PARP inhibitor, BMN 673, and identify markers of response as a basis for developing predictive markers for clinical application. EXPERIMENTAL DESIGN: Inhibition of SCLC proliferation by BMN 673 was assayed in vitro and effects on tumor growth were measured in SCLC xenograft models. Protein expression and pathway activation was assessed by reverse phase protein array and western blot analysis. PARP inhibition was confirmed using a PAR ELISA. RESULTS: We demonstrate striking, single agent activity of BMN 673 in SCLC cell lines and xenografts, with single agent BMN 673 exhibiting in vivo activity similar to cisplatin. Sensitivity to BMN 673 was associated with elevated baseline expression levels of several DNA repair proteins, whereas greater drug resistance was observed in SCLC models with baseline activation of the PI3K/mTOR pathway. Furthermore, we developed and confirmed these data with a novel "DNA repair score" consisting of a group of 17 DNA repair proteins. CONCLUSIONS: Elevated expression of multiple DNA repair proteins, as well as a corresponding "DNA repair protein score," predict response to BMN 673 in in vitro SCLC models. These observations complement recent work in which PI3K inhibition sensitizes breast cancer models to PARP inhibition, suggesting cooperation between DNA repair and PI3K pathways.

Characterizing the molecular spatial and temporal field of injury in early-stage smoker non-small cell lung cancer patients after definitive surgery by expression profiling.

Gene expression alterations in response to cigarette smoke have been characterized in normal-appearing bronchial epithelium of healthy smokers, and it has been suggested that adjacent histologically normal tissue displays tumor-associated molecular abnormalities. We sought to delineate the spatial and temporal molecular lung field of injury in smoker patients with early-stage non-small cell lung cancer (NSCLC; n = 19) who were accrued into a surveillance clinical trial for annual follow-up and bronchoscopies within 1 year after definitive surgery. Bronchial brushings and biopsies were obtained from six different sites in the lung at the time of inclusion in the study and at 12, 24, and 36 months after the first time point. Affymetrix Human Gene 1.0 ST arrays were used for whole-transcript expression profiling of airways (n = 391). Microarray analysis identified gene features (n = 1,165) that were nonuniform by site and differentially expressed between airways adjacent to tumors relative to more distant samples as well as those (n = 1,395) that were significantly altered with time up to 3 years. In addition, gene interaction networks mediated by phosphoinositide 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK)1/2 were modulated in adjacent compared with contralateral airways and the latter network with time. Furthermore, phosphorylated AKT and ERK1/2 immunohistochemical expression were significantly increased with time (nuclear pAKT, P = 0.03; cytoplasmic pAKT, P < 0.0001; pERK1/2, P = 0.02) and elevated in adjacent compared with more distant airways (nuclear pAKT, P = 0.04; pERK1/2, P = 0.03). This study highlights spatial and temporal cancer-associated expression alterations in the molecular field of injury of patients with early-stage NSCLCs after definitive surgery that warrant further validation in independent studies.

Proteomic profiling identifies dysregulated pathways in small cell lung cancer and novel therapeutic targets including PARP1.

UNLABELLED: Small cell lung cancer (SCLC) is an aggressive malignancy distinct from non-small cell lung cancer (NSCLC) in its metastatic potential and treatment response. Using an integrative proteomic and transcriptomic analysis, we investigated molecular differences contributing to the distinct clinical behavior of SCLCs and NSCLCs. SCLCs showed lower levels of several receptor tyrosine kinases and decreased activation of phosphoinositide 3-kinase (PI3K) and Ras/mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) pathways but significantly increased levels of E2F1-regulated factors including enhancer of zeste homolog 2 (EZH2), thymidylate synthase, apoptosis mediators, and DNA repair proteins. In addition, PARP1, a DNA repair protein and E2F1 co-activator, was highly expressed at the mRNA and protein levels in SCLCs. SCLC growth was inhibited by PARP1 and EZH2 knockdown. Furthermore, SCLC was significantly more sensitive to PARP inhibitors than were NSCLCs, and PARP inhibition downregulated key components of the DNA repair machinery and enhanced the efficacy of chemotherapy. SIGNIFICANCE: SCLC is a highly lethal cancer with a 5-year survival rate of less than 10%. To date, no molecularly targeted agents have prolonged survival in patients with SCLCs. As a step toward identifying new targets, we systematically profiled SCLCs with a focus on therapeutically relevant signaling pathways. Our data reveal fundamental differences in the patterns of pathway activation in SCLCs and NSCLCs and identify several potential therapeutic targets for SCLCs, including PARP1 and EZH2. On the basis of these results, clinical studies evaluating PARP and EZH2 inhibition, together with chemotherapy or other agents, warrant further investigation.

Gene expression profiling predicts the development of oral cancer.

Patients with oral premalignant lesion (OPL) have a high risk of developing oral cancer. Although certain risk factors, such as smoking status and histology, are known, our ability to predict oral cancer risk remains poor. The study objective was to determine the value of gene expression profiling in predicting oral cancer development. Gene expression profile was measured in 86 of 162 OPL patients who were enrolled in a clinical chemoprevention trial that used the incidence of oral cancer development as a prespecified endpoint. The median follow-up time was 6.08 years and 35 of the 86 patients developed oral cancer over the course. Gene expression profiles were associated with oral cancer-free survival and used to develop multivariate predictive models for oral cancer prediction. We developed a 29-transcript predictive model which showed marked improvement in terms of prediction accuracy (with 8% predicting error rate) over the models using previously known clinicopathologic risk factors. On the basis of the gene expression profile data, we also identified 2,182 transcripts significantly associated with oral cancer risk-associated genes (P value < 0.01; univariate Cox proportional hazards model). Functional pathway analysis revealed proteasome machinery, MYC, and ribosomal components as the top gene sets associated with oral cancer risk. In multiple independent data sets, the expression profiles of the genes can differentiate head and neck cancer from normal mucosa. Our results show that gene expression profiles may improve the prediction of oral cancer risk in OPL patients and the significant genes identified may serve as potential targets for oral cancer chemoprevention.

Epidermal growth factor receptor expression and gene copy number in the risk of oral cancer.

UNLABELLED: Leukoplakia is the most common premalignant lesion of the oral cavity. Epidermal growth factor receptor (EGFR) abnormalities are associated with oral tumorigenesis and progression. We hypothesized that EGFR expression and gene copy number changes are predictors of the risk of an oral premalignant lesion (OPL) progressing to oral squamous cell carcinoma (OSCC). A formalin-fixed, paraffin-embedded OPL biopsy specimen was collected from each of 162 patients in a randomized controlled clinical trial. We assessed EGFR expression by immunohistochemistry with two METHODS: a semiquantitative analysis (145 evaluable specimens) and an automated quantitative analysis (127 evaluable specimens). EGFR gene copy number was assessed by fluorescence in situ hybridization (FISH) in a subset of 49 OPLs with high EGFR expression defined by the semiquantitative analysis. We analyzed EGFR abnormalities for associations with OSCC development. High EGFR expression occurred in 103 (71%) of the 145 OPLs and was associated with a nonsignificantly higher risk of OSCC (P = 0.10). Twenty (41%) of 49 OPLs assessed by FISH had an increased EGFR gene copy number (FISH-positive). Patients with FISH-positive lesions had a significantly higher incidence of OSCC than did patients with FISH-negative (a normal copy number) lesions (P = 0.0007). Of note, 10 of 11 OSCCs that developed at the site of the examined OPL were in the FISH-positive group, leaving only one FISH-negative OPL that did so (P < 0.0001). Our data indicate that an increased EGFR gene copy number is common in and associated with OSCC development in patients with OPLs expressing high EGFR, particularly OSCC developing at the site of a high-expression OPL; they also suggest that EGFR inhibitors may prevent oral cancer in patients with OPLs having an increased EGFR gene copy number.

DeltaNp63 overexpression, alone and in combination with other biomarkers, predicts the development of oral cancer in patients with leukoplakia.

PURPOSE: The risk of malignant transformation of oral preneoplastic lesion (OPL) is difficult to assess. DeltaNp63 is an early oncoprotein associated with mucosal tumorigenesis. The purpose of this study was to assess DeltaNp63 expression in OPL and its role as a marker of oral cancer risk. EXPERIMENTAL DESIGN: DeltaNp63 expression was determined using immunohistochemistry in 152 OPL patients included in a clinical trial comparing retinyl palmitate alone or plus beta-carotene with low-dose 13-cis-retinoic acid. The associations between DeltaNp63 expression as well as DeltaNp63 expression with other potential risk factors for oral cancer development were analyzed. RESULTS: DeltaNp63 expression was positive in 41 (27%) patients, clusters of intraepithelial inflammatory cells (EIC) were noted in 37 (26%) patients, and podoplanin (previously reported) was positive in 56 (37%) patients. Significantly more patients whose lesions were DeltaNp63 positive or exhibited EIC developed oral cancers. In the multicovariate analysis including age, treatment, and histologic status as cofactors, positive DeltaNp63 expression was associated with an increased hazard ratio of 3.308 (95% confidence interval, 1.663-6.580; P = 0.0007). Patients whose lesions showed positive DeltaNp63, podoplanin, and EIC had the highest oral cancer risk with a hazard ratio of 4.372 (95% confidence interval, 1.912-9.992; P = 0.0005) and 61% oral cancer development rate at 5 years compared with 15% of other OPL patients (P < 0.0001). CONCLUSION: DeltaNp63 overepression in OPL is associated with increased oral cancer risk. Together, DeltaNp63, podoplanin, and EIC may be used as biomarkers to identify OPL patients with substantially high oral cancer risk.

Podoplanin: a novel marker for oral cancer risk in patients with oral premalignancy.

PURPOSE: Oral leukoplakia (OPL) is a heterogeneous oral lesion with an increased oral cancer risk. Current clinical parameters cannot predict the potential of malignant transformation in patients with OPL. We have shown that podoplanin, a lymphatic endothelial marker, is highly expressed in oral cancer and some oral premalignancies. The purpose of this study is to determine a role of podoplanin in predicting oral cancer development in patients with OPL. PATIENTS AND METHODS: Podoplanin expression was determined in 150 OPL patients with long-term follow-up using immunohistochemistry. Association between the protein expression patterns and clinicopathologic parameters including oral cancer development during the follow-up were analyzed. RESULTS: Fifty-six (37%) of the 150 OPL patients exhibited podoplanin expression in the basal and suprabasal layers and were classified as podoplanin positive. Podoplanin positivity was more frequent in older patients (P = .016), females (P = .020), and dysplastic lesions (P = .040). Patients with OPL that was podoplanin positive had significantly higher incidence of oral cancer than did those whose OPL was podoplanin negative (P = .0002). In the multivariate analysis using histology and podoplanin as cofactors, podoplanin was the only independent factor for oral cancer development (hazard ratio = 3.087; 95% CI, 1.530 to 6.231; P = .002). Importantly, oral cancer risk can be further stratified by considering both histology and podoplanin information. CONCLUSION: Podoplanin is frequently expressed in OPL. Together with histology, podoplanin may serve as a powerful biomarker to predict the risk for oral cancer development in patients with OPL.

Oral epithelium as a surrogate tissue for assessing smoking-induced molecular alterations in the lungs.

The lungs and oral cavity of smokers are exposed to tobacco carcinogens. We hypothesized that tobacco-induced molecular alterations in the oral epithelium are similar to those in the lungs, and thus the oral epithelium may be used as a surrogate tissue for assessing alterations in the lungs. We used methylation-specific PCR to analyze promoter methylation of the p16 and FHIT genes at baseline and 3 months after intervention in 1,774 oral and bronchial brush specimens from 127 smokers enrolled in a randomized placebo-controlled chemoprevention trial. The association between methylation patterns in oral tissues and bronchial methylation indices (methylated sites / total sites per subject) was analyzed in a blinded fashion. At baseline, promoter methylation in bronchial tissue was present in 23% of samples for p16, 17% for FHIT, and 35% for p16 and FHIT; these percentages were comparable to methylation in oral tissue: 19% (p16), 15% (FHIT), and 31% (p16 and FHIT). Data from both oral and bronchial tissues were available for 125 individuals, in whom the two sites correlated strongly with respect to alterations (P < 0.0001 for both p16 and FHIT). At baseline, the mean bronchial methylation index was far higher in patients with oral tissue methylation (in either of the two genes; 39 patients) than in patients without oral tissue methylation (86 patients): 0.53 +/- 0.29 versus 0.27 + 0.26 methylation index (P < 0.0001). Similar correlations occurred at 3 months after intervention. Our results support the potential of oral epithelium as a surrogate tissue for assessing tobacco-induced molecular damage in the lungs and thus have important implications for designing future lung cancer prevention trials and for research into the risk and early detection of lung cancer.