Circulating tumour DNA profiling reveals heterogeneity of EGFR inhibitor resistance mechanisms in lung cancer patients

Circulating tumour DNA (ctDNA) analysis facilitates studies of tumour heterogeneity. Here we employ CAPP-Seq ctDNA analysis to study resistance mechanisms in 43 non-small cell lung cancer (NSCLC) patients treated with the third-generation epidermal growth factor receptor (EGFR) inhibitor rociletinib. We observe multiple resistance mechanisms in 46% of patients after treatment with first-line inhibitors, indicating frequent intra-patient heterogeneity. Rociletinib resistance recurrently involves MET, EGFR, PIK3CA, ERRB2, KRAS and RB1. We describe a novel EGFR L798I mutation and find that EGFR C797S, which arises in ∼33% of patients after osimertinib treatment, occurs in <3% after rociletinib. Increased MET copy number is the most frequent rociletinib resistance mechanism in this cohort and patients with multiple pre-existing mechanisms (T790M and MET) experience inferior responses. Similarly, rociletinib-resistant xenografts develop MET amplification that can be overcome with the MET inhibitor crizotinib. These results underscore the importance of tumour heterogeneity in NSCLC and the utility of ctDNA-based resistance mechanism assessment.

Comparative effectiveness of stereotactic radiosurgery versus whole-brain radiation therapy for patients with brain metastases from breast or non-small cell lung cancer

BACKGROUND

The optimal treatment for patients with brain metastases remains controversial as the use of stereotactic radiosurgery (SRS) alone, replacing whole-brain radiation therapy (WBRT), has increased. This study determined the patterns of care at multiple institutions before 2010 and examined whether or not survival was different between patients treated with SRS and patients treated with WBRT.

METHODS

This study examined the overall survival of patients treated with radiation therapy for brain metastases from non-small cell lung cancer (NSCLC; initially diagnosed in 2007-2009) or breast cancer (initially diagnosed in 1997-2009) at 5 centers. Propensity score analyses were performed to adjust for confounding factors such as the number of metastases, the extent of extracranial metastases, and the treatment center.

RESULTS

Overall, 27.8% of 400 NSCLC patients and 13.4% of 387 breast cancer patients underwent SRS alone for the treatment of brain metastases. Few patients with more than 3 brain metastases or lesions ≥ 4 cm in size underwent SRS. Patients with fewer than 4 brain metastases less than 4 cm in size (n = 189 for NSCLC and n = 117 for breast cancer) who were treated with SRS had longer survival (adjusted hazard ratio [HR] for NSCLC, 0.58; 95% confidence Interval [CI], 0.38-0.87; P = .01; adjusted HR for breast cancer, 0.54; 95% CI, 0.33-0.91; P = .02) than those treated with WBRT.

CONCLUSIONS

Patients treated for fewer than 4 brain metastases from NSCLC or breast cancer with SRS alone had longer survival than those treated with WBRT in this multi-institutional, retrospective study, even after adjustments for the propensity to undergo SRS. Cancer 2016;122:2091-100. © 2016 American Cancer Society.

Overexpression of Rad51C splice variants in colorectal tumors

Functional alterations in Rad51C are the cause of the Fanconi anemia complementation group O (FANCO) gene disorder. We have identified novel splice variants of Rad51C mRNA in colorectal tumors and cells. The alternatively spliced transcript variants are formed either without exon-7 (variant 1), without exon 6 and 7 (variant 2) or without exon 7 and 8 (variant 3).

Real time PCR analysis of nine pair-matched colorectal tumors and non-tumors showed that variant 1 was overexpressed in tumors compared to matched non-tumors. Among 38 colorectal tumor RNA samples analyzed, 18 contained variant 1, 12 contained variant 2, 14 contained variant 3, and eight expressed full length Rad51C exclusively. Bisulfite DNA sequencing showed promoter methylation of Rad51C in tumor cells. 5-azacytidine treatment of LS-174T cells caused a 14 fold increase in variant 1, a 4.8 fold increase for variant 3 and 3.4 fold for variant 2 compared to 2.5 fold increase in WT.

Expression of Rad51C variants is associated with FANCD2 foci positive colorectal tumors and is associated with microsatellite stability in those tumors. Further investigation is needed to elucidate differential function of the Rad51C variants to evaluate potential effects in drug resistance and DNA repair.

Oncolytic reovirus in combination with chemotherapy in metastatic or recurrent non-small cell lung cancer patients with KRAS-activated tumors

BACKGROUND

The type 3 Dearing reovirus (Reolysin) is a naturally occurring virus that preferentially infects and causes oncolysis in tumor cells with a Ras-activated pathway. It induces host immunity and cell cycle arrest and acts synergistically with cytotoxic agents.

METHODS

This study evaluated Reolysin combined with paclitaxel and carboplatin in patients with metastatic/recurrent KRAS-mutated or epidermal growth factor receptor (EGFR)-mutated/amplified non-small cell lung cancer.

RESULTS

Thirty-seven patients were treated. Molecular alterations included 20 KRAS mutations, 10 EGFR amplifications, 3 EGFR mutations, and 4 BRAF-V600E mutations. In total, 242 cycles (median, 4; range, 1-47) were completed. The initial doses were area under the curve (AUC) 6 mg/mL/min for carboplatin, 200 mg/m(2) for paclitaxel on day 1, and 3 × 10(10) 50% tissue culture infective dose for Reolysin on days 1 to 5 of each 21-day cycle. Because of diarrhea and febrile neutropenia (in the first 2 patients), subsequent doses were reduced to 175 mg/m(2) for paclitaxel and AUC 5 mg/mL/min for carboplatin. Toxicities included fatigue, diarrhea, nausea/vomiting, neutropenia, arthralgia/myalgia, anorexia, and electrolyte abnormalities. Response Evaluation Criteria in Solid Tumors 1.0 responses included the following: partial response for 11 patients, stable disease (SD) for 20 patients, progressive disease for 4 patients, and not evaluable for 2 patients (objective response rate, 31%; 90% 1-sided lower confidence interval, 21%). Four SD patients had >40% positron emission tomography standardized uptake value reductions. The median progression-free survival, median overall survival, and 12-month overall survival rate were 4 months, 13.1 months, and 57%, respectively. Seven patients were alive after a median follow-up of 34.2 months; they included 2 patients without disease progression at 37 and 50 months.

CONCLUSIONS

Reolysin in combination with paclitaxel and carboplatin was well tolerated. The observed response rate suggests a benefit of the reovirus for chemotherapy. A follow-up randomized study is recommended. The proportion of patients surviving longer than 2 years (30%) suggests a second/third-line treatment effect or possibly the triggering of an immune response after tumor reovirus infiltration.

Lung cancer screening, version 1.2015: featured updates to the NCCN guidelines

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Lung Cancer Screening provide recommendations for selecting individuals for lung cancer screening, and for evaluation and follow-up of nodules found during screening, and are intended to assist with clinical and shared decision-making. These NCCN Guidelines Insights focus on the major updates to the 2015 NCCN Guidelines for Lung Cancer Screening, which include a revision to the recommendation from category 2B to 2A for one of the high-risk groups eligible for lung cancer screening. For low-dose CT of the lung, the recommended slice width was revised in the table on "Low-Dose Computed Tomography Acquisition, Storage, Interpretation, and Nodule Reporting."

Randomized Phase II Trial of Erlotinib Beyond Progression in Advanced Erlotinib-Responsive Non-Small Cell Lung Cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy is clearly beneficial in patients with advanced EGFR-mutated non-small cell lung cancer (NSCLC). However, acquired resistance develops uniformly and the benefit of continuation of EGFR TKI therapy beyond progression remains unclear.

MATERIALS AND METHODS

This was a randomized phase II study of chemotherapy (arm A: pemetrexed or docetaxel) versus chemotherapy plus erlotinib (ERL) (arm B) in patients with progressive NSCLC following clinical benefit from erlotinib. In arm B, chemotherapy was given with erlotinib at an oral daily dose of 150 mg on days 2-19 of each cycle to minimize negative pharmacodynamic interactions. The primary endpoint was that continuation of erlotinib in this patient population could extend progression-free survival (PFS) by 50%.

RESULTS

A total of 46 patients were randomized (arm A: 24; arm B: 22). Patient characteristics were well balanced except there were more female patients in arm A (p = .075). The median PFS of patients in arm A was 5.5 months and for those in arm B, 4.4 months (p = .699). The response rates were 13% and 16% in arms A and B, respectively (p = .79). EGFR status data were available for 39 of the 46 patients and no significant difference in PFS was seen for continuing ERL beyond progression in mutation-positive patients. Substantially more toxicity was seen in arm B than arm A.

CONCLUSION

There was added toxicity but no benefit with the continuation of ERL beyond progression along with chemotherapy as compared with chemotherapy alone.

IMPLICATIONS FOR PRACTICE

The benefits of continuing erlotinib upon progression alongside conventional chemotherapy are unclear. This randomized phase II study, initiated prior to the establishment of routine epidermal growth factor receptor (EGFR) mutation testing, addressed this clinically relevant issue through randomizing patients with prior clinical benefit from erlotinib (thereby enriching for EGFR-mutated tumors) upon progression in the second- or third-line setting to conventional chemotherapy (single-agent pemetrexed or docetaxel) with or without continued erlotinib. The results showed no benefit to continuing erlotinib beyond progression, while significantly more side effects were noted in the combination arm. Along with other recently presented study findings, these results argue against the routine practice of continuing erlotinib in this setting.

Non-small cell lung cancer, version 1.2015

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) focuses on the principles of radiation therapy (RT), which include the following: (1) general principles for early-stage, locally advanced, and advanced/metastatic NSCLC; (2) target volumes, prescription doses, and normal tissue dose constraints for early-stage, locally advanced, and advanced/palliative RT; and (3) RT simulation, planning, and delivery. Treatment recommendations should be made by a multidisciplinary team, including board-certified radiation oncologists who perform lung cancer RT as a prominent part of their practice.

Abstract 559: Inhibition of pro-survival pathways in lung cancer cells with functional defects in the Fanconi Anemia pathway

There is a growing appreciation that defects in homologous recombination repair may increase sensitivity of tumors to certain DNA-damaging agents, plausibly through a synthetic lethal interaction. The Fanconi Anemia (FA) pathway is a major mechanism of homologous recombination (HR) DNA repair. Deficiencies in FA pathway have been reported as a predictor of cisplatin, mitomycin C (MMC) or PARP inhibitor sensitivity in cancer cells. The novel PARP inhibitor BMN-673 has emerged from preclinical studies as a best in class PARP trapping agent. BMN-673 has also demonstrated single-agent cytotoxicity in BRCA mutant cells, and activity in cancer patients with BRCA germ line deficiency.

To evaluate novel targeted agents in the background of FA deficiency we utilized RNAi technology to generate several lung cancer cell lines with FANCD2 deficiency. Successful FANCD2 knockdown was confirmed by reduction in the FANCD2 protein. Cell viability was evaluated with MTT assay.

We treated the FA defective H1299D2-down and A549D2-down non-small cell lung cancer cells and their FA competent counterparts H1299E and A549E (empty vector controls) with the PARP inhibitors veliparib (ABT-888, 5μM) and BMN673 (0.5μM), as well as with the CHK1 inhibitor Arry-575 at a dose of 0.5μM. We also treated the BCL2 expressing small cell lung cancer cells H719D2-down, H792D2-down and their controls H719E and H792E with the BCL2/XL inhibitor navitoclax (ABT263) at a dose of 2μM. The treated cells were harvested at 24, 48 and 72 hours (h) post treatment.

Cell viability analysis showed that H1299D2-down cells had 80% of viable cells compared to 100% viable cells in H1299E controls 72h post treatment with veliparib. The A549D2-down cells had 68% viable cells compared to 83% viable cells in the A549E cells 72 h post veliparib treatment. FA defective cells were also more sensitive to treatment of BMN-673 (25% for H1299D2-down vs 62% for H1299E; 29% for A549D2-down vs 46% for A549E) 72 h post BMN-673 treatment at dose of 0.5μM. BMN-673 was more potent compared to veliparib.

FA defective cells were also more sensitive to the treatment of CHK1 or BCL2/XL inhibition. H1299D2-down cells had 38% of viable cells comparing to 60% viable cells in the H1299E cells post treatment of CHK1 inhibitor Arry-575 at a dose of 0.5 μM. In addition, MTT analysis showed that BCL2/XL inhibitor navitoclax was more cytotoxic to the H719D2-down (51%) as compared to H719E (85%) 48 h post treatment. Similarly, the H792D2-down cells were more sensitive to the treatment of navitoclax (58% viable cell) as compared to H792E cells (86% viable cell) 48 h post treatment at dose of 2μM.

Given that FA pathway plays essential roles in response to DNA damage, our results suggest that a subset of lung cancer patients are likely to be more susceptible to treatments in which additional pathways (e.g PARP, CHK1 and BCL2/XL) are targeted. Clinical trials to evaluate this therapeutic concept are needed.

Citation Format: Li Gao, Wenrui Duan, Kathleen Dotts, Arjun Kalvala, Brittany Aguila, Gregory A. Otterson, Miguel A. Villalona-Calero. Inhibition of pro-survival pathways in lung cancer cells with functional defects in the Fanconi Anemia pathway. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 559. doi:10.1158/1538-7445.AM2015-559

Stromal Caveolin-1 Is Associated With Response and Survival in a Phase II Trial of nab-Paclitaxel With Carboplatin for Advanced NSCLC Patients

In this phase II trial, carboplatin with nanoparticle albumin-bound (nab)-paclitaxel as first-line therapy for advanced non-small-cell lung cancer (NSCLC) was evaluated. Most patients had squamous cell histology. Tumor-associated stromal caveolin-1 (Cav-1) expression was correlated with improved response rate and survival in NSCLC patients who received nab-paclitaxel in this phase II trial. These results suggest Cav-1 might serve as a potential biomarker in this patient population.

BACKGROUND

The combination of bevacizumab with platinum-based chemotherapy results in greater response rate (RR) and overall survival (OS) in advanced non-small-cell lung cancer (NSCLC). Bevacizumab is contraindicated in patients with squamous histology or hemoptysis. Nanoparticle albumin-bound (nab)-paclitaxel is a novel formulation of paclitaxel with greater dose tolerance and improved efficacy. We hypothesized that nab-paclitaxel and carboplatin would be superior to alternative doublets in advanced NSCLC patients ineligible for bevacizumab.

PATIENTS AND METHODS

We conducted a single-arm phase II trial (NCT00729612) with carboplatin and nab-paclitaxel on day 1 of a 21-day cycle to evaluate RR (primary end point), safety, toxicity, and OS. Eligibility included: squamous histology, hemoptysis, or ongoing anticoagulation. Correlative studies included immunohistochemistry for secreted protein acid rich in cysteine (SPARC) and caveolin-1 (Cav-1).

RESULTS

Sixty-three patients were enrolled. Most patients had squamous cell carcinoma (n = 48); other reasons for eligibility included hemoptysis (n = 11) and anticoagulation (n = 2). Toxicity Grade ≥ 3/4 included neuropathy, cytopenias, and fatigue. RR was 38% (24 partial response/0 complete response); 20 patients had stable disease (32%). Median progression-free survival was 5 months and median OS was 9.7 months. Immunohistochemistry for SPARC and Cav-1 was performed in 38 and 37 patients respectively. Although no association was found for SPARC expression in tumor or stroma with RR or OS, we found that higher Cav-1 levels in tumor-associated stroma was associated with improved RR and OS.

CONCLUSION

Carboplatin and nab-paclitaxel every 21 days demonstrated promising efficacy with tolerable toxicity in NSCLC patients ineligible for bevacizumab therapy. Further analysis and validation of Cav-1 and SPARC expression in tumor and stromal compartments as prognostic and/or predictive biomarkers of NSCLC or nab-paclitaxel treatment is warranted.

Clinical benefit of continuing ALK inhibition with crizotinib beyond initial disease progression in patients with advanced ALK-positive NSCLC

BACKGROUND

Crizotinib is approved to treat advanced ALK-positive non-small-cell lung cancer (NSCLC), but most patients ultimately develop progressive disease (PD). We investigated whether continuing ALK inhibition with crizotinib beyond PD (CBPD) is clinically beneficial and attempted to identify clinicopathologic characteristics associated with patients who experience clinical benefit.

PATIENTS AND METHODS

Patients with advanced ALK-positive NSCLC enrolled in two ongoing multicenter, single-arm trials who developed RECIST-defined PD were allowed to continue crizotinib if they were deriving ongoing clinical benefit. In the present retrospective analysis, continuation of CBPD was defined as >3 weeks of crizotinib treatment after PD documentation. Patients who had PD as best response to initial crizotinib treatment were excluded. Baseline and post-progression characteristics, sites of PD, and overall survival (OS) were compared in patients who continued CBPD versus those who did not. The impact of continuing CBPD on OS after adjusting for potential confounding factors was assessed.

RESULTS

Among 194 crizotinib-treated patients with RECIST-defined PD, 120 (62%) continued CBPD. A significantly higher proportion of patients who continued CBPD than patients who did not had an ECOG performance status (PS) of 0/1 at PD (96% versus 82%; P=0.02). CBPD patients had significantly longer OS from the time of PD [median 16.4 versus 3.9 months; hazards ratio (HR) 0.27, 95% confidence interval (CI): 0.17-0.42; P<0.0001] and from the time of initial crizotinib treatment (median 29.6 versus 10.8 months; HR 0.30, 95% CI: 0.19-0.46; P<0.0001). The multiple-covariate Cox regression analysis revealed that CBPD remained significantly associated with improved OS after adjusting for relevant factors.

CONCLUSIONS

Patients who continued CBPD were more likely to have good ECOG PS (0/1) at the time of PD. Continuing ALK inhibition with crizotinib after PD may provide survival benefit to patients with advanced ALK-positive NSCLC.

Chemotherapy With or Without Maintenance Sunitinib for Untreated Extensive-Stage Small-Cell Lung Cancer: A Randomized, Double-Blind, Placebo-Controlled Phase II Study-CALGB 30504 (Alliance)

PURPOSE

To evaluate the efficacy of maintenance sunitinib after chemotherapy for small-cell lung cancer (SCLC).

PATIENTS AND METHODS

The Cancer and Leukemia Group B 30504 trial was a randomized, placebo-controlled, phase II study that enrolled patients before chemotherapy (cisplatin 80 mg/m(2) or carboplatin area under the curve of 5 on day 1 plus etoposide 100 mg/m(2) per day on days 1 to 3 every 21 days for four to six cycles). Patients without progression were randomly assigned 1:1 to placebo or sunitinib 37.5 mg per day until progression. Cross-over after progression was allowed. The primary end point was progression-free survival (PFS) from random assignment for maintenance placebo versus sunitinib using a one-sided log-rank test with α = .15; 80 randomly assigned patients provided 89% power to detect a hazard ratio (HR) of 1.67.

RESULTS

One hundred forty-four patients were enrolled; 138 patients received chemotherapy. Ninety-five patients were randomly assigned; 10 patients did not receive maintenance therapy (five on each arm). Eighty-five patients received maintenance therapy (placebo, n = 41; sunitinib, n = 44). Grade 3 adverse events with more than 5% incidence were fatigue (19%), decreased neutrophils (14%), decreased leukocytes (7%), and decreased platelets (7%) for sunitinib and fatigue (10%) for placebo; grade 4 adverse events were GI hemorrhage (n = 1) and pancreatitis, hypocalcemia, and elevated lipase (n = 1; all in same patient) for sunitinib and thrombocytopenia (n = 1) and hypernatremia (n = 1) for placebo. Median PFS on maintenance was 2.1 months for placebo and 3.7 months for sunitinib (HR, 1.62; 70% CI, 1.27 to 2.08; 95% CI, 1.02 to 2.60; one-sided P = .02). Median overall survival from random assignment was 6.9 months for placebo and 9.0 months for sunitinib (HR, 1.28; 95% CI, 0.79 to 2.10; one-sided P = .16). Three sunitinib and no placebo patients achieved complete response during maintenance. Ten (77%) of 13 patients evaluable after cross-over had stable disease on sunitinib (6 to 27 weeks).

CONCLUSION

Maintenance sunitinib was safe and improved PFS in extensive-stage SCLC.

Activity and safety of nivolumab, an anti-PD-1 immune checkpoint inhibitor, for patients with advanced, refractory squamous non-small-cell lung cancer (CheckMate 063): a phase 2, single-arm trial

BACKGROUND

Patients with squamous non-small-cell lung cancer that is refractory to multiple treatments have poor outcomes. We assessed the activity of nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, for patients with advanced, refractory, squamous non-small-cell lung cancer.

METHODS

We did this phase 2, single-arm trial at 27 sites (academic, hospital, and private cancer centres) in France, Germany, Italy, and USA. Patients who had received two or more previous treatments received intravenous nivolumab (3 mg/kg) every 2 weeks until progression or unacceptable toxic effects. The primary endpoint was the proportion of patients with a confirmed objective response as assessed by an independent radiology review committee. We included all treated patients in the analyses. This study is registered with ClinicalTrials.gov, number NCT01721759.

FINDINGS

Between Nov 16, 2012, and July 22, 2013, we enrolled and treated 117 patients. 17 (14·5%, 95% CI 8·7-22·2) of 117 patients had an objective response as assessed by an independent radiology review committee. Median time to response was 3·3 months (IQR 2·2-4·8), and median duration of response was not reached (95% CI 8·31-not applicable); 13 (77%) of 17 of responses were ongoing at the time of analysis. 30 (26%) of 117 patients had stable disease (median duration 6·0 months, 95% CI 4·7-10·9). 20 (17%) of 117 patients reported grade 3-4 treatment-related adverse events, including: fatigue (five [4%] of 117 patients), pneumonitis (four [3%]), and diarrhoea (three [3%]). There were two treatment-associated deaths caused by pneumonia and ischaemic stroke that occurred in patients with multiple comorbidities in the setting of progressive disease.

INTERPRETATION

Nivolumab has clinically meaningful activity and a manageable safety profile in previously treated patients with advanced, refractory, squamous non-small cell lung cancer. These data support the assessment of nivolumab in randomised, controlled, phase 3 studies of first-line and second-line treatment.

FUNDING

Bristol-Myers Squibb.

Fanconi anemia repair pathway dysfunction, a potential therapeutic target in lung cancer

The Fanconi anemia (FA) pathway is a major mechanism of homologous recombination DNA repair. The functional readout of the pathway is activation through mono-ubiquitination of FANCD2 leading to nuclear foci of repair. We have recently developed an FA triple-staining immunofluorescence based method (FATSI) to evaluate FANCD2 foci formation in formalin fixed paraffin-embedded (FFPE) tumor samples. DNA-repair deficiencies have been considered of interest in lung cancer prevention, given the persistence of damage produced by cigarette smoke in this setting, as well as in treatment, given potential increased efficacy of DNA-damaging drugs. We screened 139 non-small cell lung cancer (NSCLC) FFPE tumors for FANCD2 foci formation by FATSI analysis. Among 104 evaluable tumors, 23 (22%) were FANCD2 foci negative, thus repair deficient. To evaluate and compare novel-targeted agents in the background of FA deficiency, we utilized RNAi technology to render several lung cancer cell lines FANCD2 deficient. Successful FANCD2 knockdown was confirmed by reduction in the FANCD2 protein. Subsequently, we treated the FA defective H1299D2-down and A549D2-down NSCLC cells and their FA competent counterparts (empty vector controls) with the PARP inhibitors veliparib (ABT-888) (5 μM) and BMN673 (0.5 μM), as well as the CHK1 inhibitor Arry-575 at a dose of 0.5 μM. We also treated the FA defective small cell lung cancer cell lines H719D2-down and H792D2-down and their controls with the BCL-2/XL inhibitor ABT-263 at a dose of 2 μM. The treated cells were harvested at 24, 48, and 72 h post treatment. MTT cell viability analysis showed that each agent was more cytotoxic to the FANCD2 knock-down cells. In all tests, the FA defective lung cancer cells had less viable cells as comparing to controls 72 h post treatment. Both MTT and clonogenic analyses comparing the two PARP inhibitors, showed that BMN673 was more potent compared to veliparib. Given that FA pathway plays essential roles in response to DNA damage, our results suggest that a subset of lung cancer patients are likely to be more susceptible to DNA cross-link based therapy, or to treatments in which additional repair mechanisms are targeted. These subjects can be identified through FATSI analysis. Clinical trials to evaluate this therapeutic concept are needed.

Abstract 5434: Combined BCL-2/XL and mTor inhibition promotes apoptosis in small cell lung cancer

The Bcl-2 family genes have emerged as potential targets for the treatment of small cell lung cancer (SCLC). Bcl-2 is a central apoptotic inhibitor associated with tumor progression and treatment resistance. Overexpression occurs in up to 80% of SCLC. ABT-263 (navitoclax) is an orally bioavailable small molecule, which inhibits Bcl-2 and Bcl-xL, disrupting their interactions with pro-death proteins, and leading to the initiation of apoptosis. However a recent clinical trial of single-agent ABT-263 (navitoclax) showed a low rate of response in advanced and recurrent SCLC, discouraging development.

Our laboratory had previously shown that SCLC cells rendered deficient in the Fanconi Anemia (FA) repair pathway by inhibition of FANCD2 were more sensitive to navitoclax compared to FA competent cells, and that 15% of small cell lung cancer patients' tumor samples, evaluated by immunofluorescence for FANCD2 foci formation are FA functionally deficient. In the search for pharmacologic inhibition of FANCD2, which could potentially expand the pool of susceptible patients to navitoclax, we learned that the mTOR inhibitor AZD8055 induced downregulation of the FANCD2 protein. Thus, we hypothesized that mTOR inhibition would potentiate the activity of navitoclax.

First we treated the human SCLC cancer cell H179 with navitoclax and AZD8055 at a dose of 5µM, either as single agents or in combination. MTT assay showed that the cell survival rate was 39% for AZD8055 and 52% for navitoclax when the cell was treated for 72 hours. Western analysis showed that AZD8055 inhibited FANCD2 protein expression completely, and when the cell was treated with the combination, the survival rate decreased to 24%. Increased apoptosis by Western immunoblot PARP cleavage assay was observed for the combination, as compared to navitoclax or AZD8055 alone.

Despite evidence showing that the clinically available mTOR inhibitor temsirolimus only inhibits TORC1 at clinically meaningful concentrations, we decided to evaluate if this agent could also inhibit FANCD2. Western immunoblot analysis with anti-FANCD2 antibody showed that temsirolimus caused marked FANCD2 protein reduction. Subsequent clonogenic assays using the human SCLC cells H719 and H792 showed that either temsirolimus or navitoclax treatment alone was cytotoxic to both SCLC cell lines. The cell survival rate for H719 was 48% for temsirolimus and 62% for navitoclax10 days following treatment. For H792 the survival rates were 59% for temsirolimus and 32% for navitoclax. Navitoclax and temsirolimus in combination led to further reduction in cell colony survival (5% for H719 and 14% H792). Western analysis showed that the apoptotic rate was increased for the combination as compared to single agent treatment.

The encouraging in vitro results described above suggest that evaluation of activity for the combination of navitoclax and temsirolimus in small cell lung cancer patients should be considered.

Citation Format: Li Gao, Brittany Barnwell, Arjun Kalvala, Gregory A. Otterson, Wenrui Duan, Miguel A. Villalona-Calero. Combined BCL-2/XL and mTor inhibition promotes apoptosis in small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5434. doi:10.1158/1538-7445.AM2014-5434

Erlotinib in African Americans with advanced non-small cell lung cancer: a prospective randomized study with genetic and pharmacokinetic analyses

Prospective studies on epidermal growth factor receptor (EGFR) inhibitors in African Americans with non-small cell lung cancer (NSCLC) have not previously been performed. In this phase II randomized study, 55 African Americans with NSCLC received 150 mg/day erlotinib or a body weight-adjusted dose with subsequent escalations to the maximum-allowable dose, 200 mg/day, to achieve rash. Erlotinib and OSI-420 exposures were lower than those observed in previous studies, consistent with CYP3A pharmacogenetics implying higher metabolic activity. Tumor genetics showed only two EGFR mutations, EGFR amplification in 17/47 samples, eight KRAS mutations, and five EML4-ALK translocations. Although absence of rash was associated with shorter time to progression (TTP), disease-control rate, TTP, and 1-year survival were not different between the two dose groups, indicating the dose-to-rash strategy failed to increase clinical benefit. Low incidence of toxicity and low erlotinib exposure suggest standardized and maximum-allowable dosing may be suboptimal in African Americans.

Molecular pathways and therapeutic targets in lung cancer

Lung cancer is still the leading cause of cancer death worldwide. Both histologically and molecularly lung cancer is heterogeneous. This review summarizes the current knowledge of the pathways involved in the various types of lung cancer with an emphasis on the clinical implications of the increasing number of actionable molecular targets. It describes the major pathways and molecular alterations implicated in the development and progression of non-small cell lung cancer (adenocarcinoma and squamous cancer), and of small cell carcinoma, emphasizing the molecular alterations comprising the specific blueprints in each group. The approved and investigational targeted therapies as well as the immune therapies, and clinical trials exploring the variety of targeted approaches to treatment of lung cancer are the main focus of this review.

Y-chromosome status identification suggests a recipient origin of posttransplant non-small cell lung carcinomas: chromogenic in situ hybridization analysis

Owing to the need of lifelong immunosuppression, solid-organ transplant recipients are known to have an increased risk of posttransplant malignancies including lung cancer. Posttransplant neoplastic transformation of donor-derived cells giving rise to hematopoietic malignancies, Kaposi sarcoma, and basal cell carcinoma in nongraft tissues has been reported. The goal of this study was to assess the cell origin (donor versus recipient derived) of posttransplant non-small cell lung carcinomas (NSCLCs) in kidney and heart transplant recipients. An institutional database search identified 2557 kidney and heart transplant recipients in 8 consecutive years. Among this cohort, 20 (0.8%) renal and 18 (0.7%) heart transplant recipients developed NSCLC. The study cohort comprised 6 of 38 NSCLCs arising in donor-recipient sex-mismatched transplant patients. The tumor cell origin was evaluated by chromogenic in situ hybridization with Y-chromosome probe on formalin-fixed, paraffin-embedded tissues. Y-chromosome was identified in 97% ± 1% (range from 92% to 99%) of all types of nucleated cells in male control tissues. In all 5 NSCLCs from male recipients of female donor organ, Y-chromosome was identified in 97% ± 2% (range from 92% to 100%) of tumor cells, statistically equivalent to normal control (P < .001). No Y-chromosome was identified in NSCLC cells from a female recipient of male kidney. These findings suggest a recipient derivation of NSCLC arising in kidney and heart transplant recipients. A combination of histologic evaluation and chromogenic in situ hybridization with Y-chromosome analysis allows reliable determination of tissue origin in sex-mismatched solid-organ transplant recipients and may aid in management of posttransplant malignancy in such cases.

Thymomas and thymic carcinomas: Clinical Practice Guidelines in Oncology

Masses in the anterior mediastinum can be neoplasms (eg, thymomas, thymic carcinomas, or lung metastases) or non-neoplastic conditions (eg, intrathoracic goiter). Thymomas are the most common primary tumor in the anterior mediastinum, although they are rare. Thymic carcinomas are very rare. Thymomas and thymic carcinomas originate in the thymus. Although thymomas can spread locally, they are much less invasive than thymic carcinomas. Patients with thymomas have 5-year survival rates of approximately 78%. However, 5-year survival rates for thymic carcinomas are only approximately 40%. These guidelines outline the evaluation, treatment, and management of these mediastinal tumors.

Cellular localization of protein arginine methyltransferase-5 correlates with grade of lung tumors

Background

Protein arginine methyltransferase-5 (PRMT5) is a chromatin-modifying enzyme capable of methylating histone and non-histone proteins, and is involved in a wide range of cellular processes that range from transcriptional regulation to organelle biosynthesis. As such, its overexpression has been linked to tumor suppressor gene silencing, enhanced tumor cell growth and survival.

Material and methods

Quantitative real-time polymerase chain reaction, Western immunoblot and immunohistochemistry were used to characterize PRMT5 expression in lung cancer cell lines and human tumors. Clinicopathological findings of tissue microarray based samples from 229 patients with non-small cell lung carcinomas (NSCLC) and 133 cases with pulmonary neuroendocrine tumors (NET) were analyzed with regard to nuclear and cytoplasmic PRMT5 expression.

Results

There was statistically significant difference in PRMT5 messenger RNA expression between tumors and nonneoplastic lung tissues. Immunoblot experiments showed abundant expression of PRMT5 and its symmetric methylation mark H4R3 in lung carcinoma but not in non-neoplastic human pulmonary alveolar and bronchial epithelial cell lines. More than two thirds of lung tumors expressed PRMT5. High levels of cytoplasmic PRMT5 were detected in 20.5% of NSCLC and in 16.5% of NET; high levels of nuclear PRMT5 were detected in 38.0% of NSCLC and 24.0% of NET. Cytoplasmic PRMT5 was associated with high grade in both NSCLC and pulmonary NET while nuclear PRMT5 was more frequent in carcinoid tumors (p < 0.05).

Conclusion

The observed findings support the role of PRMT5 in lung tumorigenesis and reflect its functional dichotomy in cellular compartments.

Virtual slide

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1611895162102528

Non-small cell lung cancer, version 2.2013

These NCCN Guidelines Insights focus on the diagnostic evaluation of suspected lung cancer. This topic was the subject of a major update in the 2013 NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer. The NCCN Guidelines Insights focus on the major updates in the NCCN Guidelines and discuss the new updates in greater detail.

Abstract 4365: Sensitivity of small cell lung cancer cells with defective Fanconi Anemia (FA) pathway to BCL2 inhibitors

Bcl-2 is a central apoptotic inhibitor, and overexpression is associated with tumor progression and treatment resistance in cancers. Overexpression has been reported in up to 80% of small cell lung cancers (SCLC). ABT-263 (Nativoclax) is a potent and selective inhibitor of Bcl-2 and Bcl-xL, disrupting their interactions with pro-death proteins leading to the initiation of apoptosis within 2 hours post exposure. However a recent phase II study of single-agent ABT-263 showed low rate of response to single-agent treatment in advanced and recurrent SCLC. Thus, pre-selection of patients most likely to derive benefit from BCL-2 inhibitors will be needed for further development of these agents in SCLC. The Fanconi Anemia (FA) pathway is a major mechanism of homologous recombination DNA repair in response to genotoxic insults. The repair abnormalities resulting from deficiencies in FA pathway potentially select for the persistence of prosurvival pathways. We hypothesized that cancers with defective FA pathway would be more sensitive to not only DNA interstrand crosslinking based therapy, but also to treatments in which prosurvival pathways are targeted, like BCL-2 inhibition.

We utilized RNAi technology to create FANCD2 knockdown SCLC cancer cells. H719 cells were transduced with FANCD2-specific shRNA-expressing and puromycin-resistant lentiviral particles or control shRNA lentiviral particles to create stably transduced cells. Successful FANCD2 knockdown was confirmed by Western blot by reduction in the FANCD2 protein. Cell viability was evaluated with MTT (Dimethylthiazolyl-2-5-diphenyltetrazolium bromide) analysis, and apoptosis was evaluated with Western immunoblot PARP cleavage assay.

The FA defective H719 small cell lung cancer cells and the control cells (transfected with empty vectors) were treated with ABT-263 at a dose of 2μM. The treated cells were then harvested at 6, 24 and 48 hours post treatment. MTT cell viability analysis showed that ABT-263 alone was cytotoxic to the FA deficient lung cancer cells with less viable cells comparing to controls 6-48 hours post treatment. In addition, Western immunoblot analysis with anti-PARP [poly (ADP-ribose) polymerase] antibody showed PARP cleavage was increased in the FA defective H719 cells as compared to control cells 6 hours post ABT-263.

Disruption of FA cascade has been reported in solid tumors. Recently we have developed a FA triple-staining immunofluorescence (FATSI) method to detect FANCD2 foci formation, which is capable of evaluating the functionality of the whole pathway using formalin fixed paraffin embedded (FFPE) tumor samples and have identified up to 15% of small cell lung cancer tumor samples to be functionally deficient. Based on our preliminary studies with the H719 cells, we propose that SCLCs with defective FA pathway would be more sensitive to BCL-2 inhibitors compared to those retaining an intact repair function.

Citation Format: Li Gao, Wenrui Duan, Brittany Barnwell, Arjun Kalvala, Gregory A. Otterson, Miguel A. Villalona-Calero. Sensitivity of small cell lung cancer cells with defective Fanconi Anemia (FA) pathway to BCL2 inhibitors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4365. doi:10.1158/1538-7445.AM2013-4365

Abstract 4246: Promoter hypermethylation and gene expression of FANCF in non-small cell lung cancer (NSCLC)

The Fanconi Anemia (FA) pathway is essential for human cells to maintain integrity following DNA damage. This pathway is involved in repairing double stranded DNA breaks. Cancers with defective FA pathway are expected to be more sensitive to cross-link based therapy, or to treatments in which additional repair mechanisms are targeted. The FA pathway contains 15 genes, and some of the members have been implicated in susceptibility to a number of cancers by genetic or epigenetic alterations. The methylation of CpG islands in the FANCF gene is thought to plays a role in the occurrence of ovarian cancer. We have recently reported the detection of up to 20% of NSCLC to be FA functionally inactive (lack of FANCD2 foci formation in the nucleus of proliferating cells by triple stain immunofluorescence, FATSI negative). Since epigenetic inactivation can be one of the mechanisms for FA functional deficiency in these tumors, we evaluated a series of NSCLC samples for FANCF methylation.

Human lung tumor tissue samples were obtained from The Tissue Procurement Shared Resources of the Ohio State University Comprehensive Cancer Center after IRB approval. FA pathway status was evaluated by FATSI. Genomic DNA and total RNA samples were isolated from frozen lung tumor and matching non-tumor tissues. The methylation status of the FANCF gene promoter was evaluated using methylation-specific PCR (MS-PCR). FANCF gene expression was evaluated by NanoString assays.

We screened total of 40 NSCL tumors by the FATSI assay, and the ratio of FANCD2 foci negative tumor was 20% (8/40). Squamous cell carcinoma, adenocarcinoma and large cell carcinoma histologies were all represented in the samples. FANCF promoter methylation was present in 2 of 8 FATSI negative tumors (1 adenocarcinoma and 1 large cell carcinoma) based on MS-PCR analysis, and absent in 8 tested FATSI positive tumors. NanoString analysis was performed in 5 FATSI positive and 5 FATSI negative tumors which the latter including the two tumors with FANCF methylation identified with the MS-PCR. FANCF mRNA level was 1.8-fold lower in tumors with promoter methylation as comparing to matched non-tumor tissues. One of the two tumors containing FANCF methylation was also analyzed with RNAseq, and the results showed a 1.6 fold reduction in FANCF mRNA in the tumor as comparing to matched non-tumor tissue. However the FANCF mRNA level was similar between tumor and non-tumor (tumor/non-tumor = 1.04) in the samples without methylation.

The above observation suggests that epigenetic alterations can be the base for FA functional deficiency in NSCLC patients. These findings may have clinical implications, since these tumors may be more sensitive to cross-link based therapy. However, an important caveat is that these changes may not be stable and could revert during treatment. Evaluation of pre and post treatment samples in FATSI negative patients undergoing therapy would be necessary to support this hypothesis.

Citation Format: Wenrui Duan, Tyler Rees, Kevin Vu, Brittany Barnwell, Li Gao, Arjun Kalvala, xin wu, Gregory A. Otterson, Miguel A. Villalona-Calero. Promoter hypermethylation and gene expression of FANCF in non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4246. doi:10.1158/1538-7445.AM2013-4246

Non-small cell lung cancer

Most patients with non-small cell lung cancer (NSCLC) are diagnosed with advanced cancer. These guidelines only include information about stage IV NSCLC. Patients with widespread metastatic disease (stage IV) are candidates for systemic therapy, clinical trials, and/or palliative treatment. The goal is to identify patients with metastatic disease before initiating aggressive treatment, thus sparing these patients from unnecessary futile treatment. If metastatic disease is discovered during surgery, then extensive surgery is often aborted. Decisions about treatment should be based on multidisciplinary discussion.

Assessment of FANCD2 nuclear foci formation in paraffin-embedded tumors: a potential patient-enrichment strategy for treatment with DNA interstrand crosslinking agents

A major mechanism of DNA repair related to homologous recombination is the Fanconi anemia (FA) pathway. FA genes collaborate with BRCA genes to form foci of DNA repair on chromatin after DNA damage or during the S phase of the cell cycle. Our goal was to develop a method capable of evaluating the functional status of the pathway in patients' tumor tissue, which could also be practically incorporated into large-scale screening. To develop this method, we first used Western immunoblot to detect FANCD2 protein monoubiquitination in fresh tumor specimens of patients with ovarian cancer undergoing surgery and stained formalin-fixed paraffin-embedded tumor tissue simultaneously with 4',6-diamidino-2-phenylindole, FANCD2, and Ki67 antibodies, eventually extending this method to other solid tumors. This triple stain permitted evaluation of the presence, or lack thereof, of FANCD2 subnuclear repair foci in proliferating cells by immunofluorescence microscopy. Overall, we evaluated 156 formalin-fixed paraffin-embedded tumor samples using the FA triple-staining immunofluorescence method. The ratios of FANCD2 foci-negative tumors in ovarian, lung, and breast tumor samples were 21%, 20%, and 29.4%, respectively. Our studies have led to the development of a suitable method for screening, capable of identifying tumors with somatic functional defects in the FA pathway. The use of paraffin-embedded tissues renders the reported method suitable for large-scale screening to select patients for treatment with DNA interstrand crosslinking agents, poly ADP-ribose polymerase inhibitors, or their combination.