Ki-67 labeling index of neuroendocrine tumors of the lung has a high level of correspondence between biopsy samples and surgical specimens when strict counting guidelines are applied

Optimal histopathological analysis of biopsies from metastases of neuroendocrine tumor (NET) of the lung requires more than morphology only. Additional parameters such as Ki-67 labeling index are required for adequate diagnosis, but few studies have compared reproducibility of different counting protocols and modalities of reporting on biopsies of lung NET. We compared the results of four different manual counting techniques to establish Ki-67 LI. On 47 paired biopsies and surgical specimens from 22 typical carcinoids (TCs), 14 atypical carcinoids (ACs), six large cell neuroendocrine carcinomas (LCNECs), and five small cell carcinomas (SCCs) immunohistochemical staining of Ki-67 antigen was performed. We counted, in regions of highest nuclear staining (HSR), a full ×40-high-power field (diameter = 0.55 mm), 500 or 2000 cells, or 2 mm² surface area, including the HSR or the entire biopsy fragment(s). Mitoses and necrosis were evaluated in an area of 2 mm² or the entire biopsy fragment(s). Between the four counting methods, no differences in Ki-67 LI were observed. However, a Ki-67 LI higher than 5% was found in only four cases when in an HSR, 500 cells were counted (18%), five (23%) when in an HSR 2000 cells were counted, four (18%) when 2 mm² were counted, and one (5%) TC case when the entire biopsy was counted. A 20% cutoff distinguished TC and AC from LCNEC and SCC with 100% specificity and sensitivity, while mitoses and necrosis failed to a large extent. Ki-67 LI in biopsy samples was concordant with that in resection specimens when 2000 cells, 2 mm², or the entire biopsy fragment(s) were counted. Our results are important for clinical management of patients with metastases of a lung NET.

The Use of Immunohistochemistry Improves the Diagnosis of Small Cell Lung Cancer and Its Differential Diagnosis. An International Reproducibility Study in a Demanding Set of Cases

INTRODUCTION

The current WHO classification of lung cancer states that a diagnosis of SCLC can be reliably made on routine histological and cytological grounds but immunohistochemistry (IHC) may be required, particularly (1) in cases in which histologic features are equivocal and (2) in cases in which the pathologist wants to increase confidence in diagnosis. However, reproducibility studies based on hematoxylin and eosin-stained slides alone for SCLC versus large cell neuroendocrine carcinoma (LCNEC) have shown pairwise κ scores ranging from 0.35 to 0.81. This study examines whether judicious use of IHC improves diagnostic reproducibility for SCLC.

METHODS

Nineteen lung pathologists studied interactive digital images of 79 tumors, predominantly neuroendocrine lung tumors. Images of resection and biopsy specimens were used to make diagnoses solely on the basis of morphologic features (level 1), morphologic features along with requested IHC staining results (level 2), and all available IHC staining results (level 3).

RESULTS

For the 19 pathologists reading all 79 cases, the rate of agreement for level 1 was 64.7%, and it increased to 73.2% and 77.5% in levels 2 and 3, respectively. With IHC, κ scores for four tumor categories (SCLC, LCNEC, carcinoid tumors, and other) increased in resection samples from 0.43 to 0.60 and in biopsy specimens from 0.43 to 0.64.

CONCLUSIONS

Diagnosis using hematoxylin and eosin staining alone showeds moderate agreement among pathologists in tumors with neuroendocrine morphology, but agreement improved to good in most cases with the judicious use of IHC, especially in the diagnosis of SCLC. An approach for IHC in the differential diagnosis of SCLC is provided.

Erlotinib-Induced Breast Cancer Regression

Objective:

To report a case of erlotinib-induced breast cancer regression.

Case Summary:

A 38-year-old woman developed bilateral locoregional malignant cutaneous lymphangitis following a right subcutaneous mastectomy and 3 months of adjuvant chemotherapy. After several systemic chemotherapy regimens, the lymphangitis worsened rapidly, with progressive skin ulceration. Morphine and dexamethasone were given, with suboptimal pain control. A chemotherapy regimen of gemcitabine and vinorelbine was started. After 2 full-dose administrations, while lymphangitis continued to worsen, erlotinib 150 mg/day was added to the regimen. After 10 weeks of treatment, pain subsided and analgesics were discontinued. Physical examination revealed a partial regression of malignant cutaneous lymphangitis and pulmonary metastases, with resolution of ulceration.

Discussion:

There has been increased interest in epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in the treatment of breast cancer. Gefitinib has shown a low level of efficacy, while preliminary clinical data on erlotinib were not conclusive and suggested lack of clinical activity. Molecular analysis of the tumor in our patient revealed a profile predictive of response to EGFR selective inhibitors in some patients with lung cancer.

Conclusions:

The addition of erlotinib to our patient's chemotherapy regimen resulted in antitumor activity in breast cancer in which an activated EGFR pathway was demonstrated. This finding is consistent with available preclinical and clinical data on EGFR tyrosine kinase inhibitors across tumor types and supports the efforts to optimize EGFR selective inhibitors in treating breast cancer and other malignancies.

The impact of immunohistochemistry on the classification of lung tumors

INTRODUCTION

To highlight the role of immunohistochemistry to lung cancer classification on the basis of existing guidelines and future perspectives.

AREAS COVERED

Four orienting key-issues were structured according to an extensive review on the English literature: a) cancer subtyping; b) best biomarkers and rules to follow; c) negative and positive profiling; d) suggestions towards an evidence-based proposal for lung cancer subtyping. A sparing material approach based on a limited number of specific markers is highly desirable. It includes p40 for squamous cell carcinoma ('no p40, no squamous'), TTF1 for adenocarcinoma, synaptophysin for neuroendocrine tumors and vimentin for sarcomatoid carcinoma. A close relationship between genotype and phenotype also supports a diagnostic role for negative profiles. Expert commentary: Highly specific and sensitive IHC markers according to positive and negative diagnostic algorithms seem appropriate for individual patients' lung cancer subtyping.

Grading lung neuroendocrine tumors: Controversies in search of a solution

BACKGROUND

Pathological grading of tumors is a way to measure biological aggressiveness. In lung neuroendocrine tumors (NET), grading is tautologically included into the current 2015 WHO histologic classification. Little is known, however, about alternative grading systems in lung NET.

METHODS

Through an extensive search of the English literature on lung NET (updated to April 2016), the following key questions were addressed: a) current concepts of grading; b) clinicians' requests for grading; c) functional parameters for grading; d) Ki-67 labeling index (LI) for grading; e) towards an effective pathology grading system.

RESULTS

There is some room for inconsistency in the histologic classification of lung NET, likely due to the varying attribution of defining criteria. Innovative diffusion-weighted imaging upon magnetic resonance or molecular analysis could help separate indolent from aggressive lung NET, thus integrating a grading approach other than histology. Troubles in the clinical handling of metastatic or individual tumors when relying on morphology alone support the development of a lung-specific grading system for the more accurate prediction of prognosis and planning therapy in individual patients. To integrate the 2015 WHO classification using innovative grading based on Ki-67 LI, mitotic count and necrosis, a new proposal is emerging where three categories of lung NET are identified, namely Lu-NET G1, Lu-NET G2 and Lu-NET G3, which would allow tumors with similar behavior and therapy to be better handled according to their own biological potential.

CONCLUSION

This new formulation of lung NET grading could have clinical relevance for the individual handling of patients.

Circulating microRNA signature as liquid-biopsy to monitor lung cancer in low-dose computed tomography screening

Liquid biopsies can detect biomarkers carrying information on the development and progression of cancer. We demonstrated that a 24 plasma-based microRNA signature classifier (MSC) was capable of increasing the specificity of low dose computed tomography (LDCT) in a lung cancer screening trial. In the present study, we tested the prognostic performance of MSC, and its ability to monitor disease status recurrence in LDCT screening-detected lung cancers.Between 2000 and 2010, 3411 heavy smokers enrolled in two screening programmes, underwent annual or biennial LDCT. During the first five years of screening, 84 lung cancer patients were classified according to one of the three MSC levels of risk: high, intermediate or low. Kaplan-Meier survival analysis was performed according to MSC and clinico-pathological information. Follow-up MSC analysis was performed on longitudinal plasma samples (n = 100) collected from 31 patients before and after surgical resection.Five-year survival was 88.9% for low risk, 79.5% for intermediate risk and 40.1% for high risk MSC (p = 0.001). The prognostic power of MSC persisted after adjusting for tumor stage (p = 0.02) and when the analysis was restricted to LDCT-detected cases after exclusion of interval cancers (p < 0.001). The MSC risk level decreased after surgery in 76% of the 25 high-intermediate subjects who remained disease free, whereas in relapsing patients an increase of the MSC risk level was observed at the time of detection of second primary tumor or metastatic progression.These results encourage exploiting the MSC test for lung cancer monitoring in LDCT screening for lung cancer.

A Primary Pure Yolk Sac Tumor of the Lung Exhibiting CDX-2 Immunoreactivity and Increased Serum Levels of Alkaline Phosphatase Intestinal Isoenzyme

Malignant extragonadal germ cell tumors primary to the lung are quite uncommon lesions, but pure yolk sac tumor is even more exceptional. This is believed to be the first reported case of yolk sac tumor of the lung in which an intense and diffuse immunoreactivity for CDX2, a marker of intestinal differentiation reportedly expressed also in gonadal yolk sac tumor, was associated with increased serum levels of the alkaline phosphatase intestinal isoform. Nine months after radical surgery and adjuvant chemotherapy, the patient is alive and well without evidence of recurrent or metastatic disease and with serum levels of the alkaline phosphatase intestinal isoform within normal limits. The pathologist should be aware of yolk sac tumor arising in the lung and that alkaline phosphatase intestinal isoform could become an additional serum marker for such a tumor.

Abstract 3113: SMO mutation identifies a subgroup of malignant pleural mesothelioma (MPM) patients with a worse prognosis

Malignant pleural mesothelioma (MPM) is a rare malignant disease with a short prognosis and limited treatment options. However, at population level about 12% of all MPM survive more than three years. The aim of this pivotal study is to investigate whether a different gene profile could divide short versus long survivors.

METHODS:

A cut-off of 36 months of survival was chosen to divide patients with shorter and longer survival. Under this condition we retrospectively collected data on 32 short- and 25 long-survivors from three Italian Institutions. Paraffin-embedded tissue samples were tested for a customized panel of 21 genes (CDKN2, NF2, GSTM1, NAT2, BAP1, TERT, P53, PTCH1, SMO, LATS2, KEAP1, PI3K, KRAS, NRAS, STK11, WT1, FBXW7, CTNNB1, KIT, KDR and REV3). DNA was obtained upon manual microdissection to ensure at least 50% cancer cells. DNA was processed by PGM Ion Torrent. The major prognostic factors and mutations were described. The hazard risk of death was calculated with the Cox Model.

RESULTS:

The main prognostic factors were equally distributed among the two groups (age, sex, histotype, stage, and treatment). The most frequent mutations were BAP-1 (24,5%), NF-2 (17,5%), p53 (14%), SMO (8,7%) PITCH (8,8%), KEAP1 (7%) and TERT (5.3%) considering all 57 patients together. Wild-type patients for this gene panel were 31.6%. Median survival for short survivors was 13 months, while 47 for long survivors. No major differences in gene profile were observed between long and short survivors with the exception of SMO which was mutated only in short survivors (16%). SMO seems strongly associated with a poor prognosis (HR 8.01; CI95% 2.79-22.98 p &lt;0.001). Also when considering only short survivors the negative prognostic effect remained statistically significant (HR 3.67, CI95% 1.28-10.48, p = 0.015). The median survival for SMO mutated patients was 7 months.

CONCLUSIONS:

SMO mutation was likely to identify a subset of MPM patients with worse prognosis.

As SMO could be a promising target for specific inhibitors, further researches at clinical level in this subset of patients and also at preclinical level are ongoing.

This study was granted by AIRC.

Citation Format: Monica Ganzinelli, Claudia Proto, Diego Signorelli, Laura Botta, Giulia Pasello, Marcello Tiseo, Annalisa Trama, Gemma Gatta, Adele Busico, Alessandra Fabbri, Nadia Zaffaroni, Giuseppe Pelosi, Ugo Pastorino, Filippo De Braud, Milena Vitali, Marina C. Garassino. SMO mutation identifies a subgroup of malignant pleural mesothelioma (MPM) patients with a worse prognosis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3113.

Applicability of Under Vacuum Fresh Tissue Sealing and Cooling to Omics Analysis of Tumor Tissues

CONTEXT

Biobanks of frozen human normal and malignant tissues represent a valuable source for "omics" analysis in translational cancer research and molecular pathology. However, the success of molecular and cellular analysis strongly relies on the collection, handling, storage procedures, and quality control of fresh human tissue samples.

OBJECTIVE

We tested whether under vacuum storage (UVS) effectively preserves tissues during the time between surgery and storage for "omics" analyses.

DESIGN

Normal and matched tumor specimens, obtained from 16 breast, colon, or lung cancer patients and 5 independent mesenchymal tumors, were dissected within 20 minutes from surgical excision and divided in three to five aliquots; for each tissue sample, one aliquot was snap-frozen in liquid nitrogen (defined as baseline or T0 samples), and the other portions were sealed into plastic bags and kept at 4°C for 1, 24, 48, or 72 hours under vacuum and then frozen. The tissue and molecular preservation under vacuum was evaluated over time in terms of histomorphology, transcription (Illumina microarrays), protein (surface-enhanced laser desorption/ionization-time of flight/mass spectrometry and Western blot), and metabolic profile (nuclear magnetic resonance spectroscopy).

RESULTS

Tissue morphology, Mib-1, and vimentin immunostaining were preserved over time without signs of tissue degradation. Principal variance component analysis showed that time of storage had a minimal effect on gene expression or the proteome, but affected the preservation of some metabolites to a greater extent. UVS did not impact the RNA and protein integrity or specific phosphorylation sites on mTOR and STAT3. Measurement of metabolites revealed pronounced changes after 1 hour of storage.

CONCLUSIONS

Our results show that UVS can preserve tissue specimens for histological, transcriptomic, and proteomic examinations up to 48 hours and possibly longer, whereas it has limitations for metabolomic applications.

Clinical Response of Carcinomas Harboring the BRD4-NUT Oncoprotein to the Targeted Bromodomain Inhibitor OTX015/MK-8628

The antineoplastic, prodifferentiative effects of bromodomain and extra-terminal (BET) bromodomain (BRD) inhibitors were initially discovered in NUT midline carcinoma (NMC), an aggressive subtype of squamous cancer driven by the BRD4-NUT fusion oncoprotein. BRD4-NUT blocks differentiation and maintains tumor growth through a potent chromatin-modifying mechanism. OTX015/MK-8628, a novel oral BET inhibitor, targets BRD2/3/4/T with preclinical activity in NMC and several other tumor types and is currently in clinical development. Antitumor activity was evaluated in four patients with advanced-stage NMC with confirmed BRD4-NUT fusions who were treated with 80 mg OTX015/MK-8628 once daily in a compassionate-use context. Two patients responded rapidly with tumor regression and symptomatic relief, and a third had meaningful disease stabilization with a minor metabolic response. The main side effects were mild to moderate gastrointestinal toxicity and fatigue, and reversible grade 3 thrombocytopenia. This is the first proof-of-concept evidence of clinical activity of a BRD inhibitor in targeting BRD4-NUT.

SIGNIFICANCE

We present the first clinical proof-of-concept that targeting BRD4-NUT with a BET inhibitor results in impressive and rapid antitumor activity in NMC. It offers strong potential for future clinical application in this rare patient population as either a single agent or in combination with other agents. Cancer Discov; 6(5); 492-500. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 461.

Diagnosis and management of typical and atypical lung carcinoids

An estimated 20% to 30% of all neuroendocrine tumours originate in the bronchial tree and lungs. According to the 2015 World Health Organization categorization, these tumours are separated into four subtypes characterized by increasing biological aggressiveness: typical carcinoid, atypical carcinoid, large-cell neuroendocrine carcinoma and small-cell carcinoma. Although typical and atypical lung carcinoids account for less than 1-5% of all pulmonary malignancies, the incidence of these neoplasms has risen significantly in recent decades. Surgery is the treatment of choice for loco-regional disease but for advanced lung carcinoids there is no recognized standard of care and successful management requires a multidisciplinary approach. The aim of this review is to provide a useful guide for the clinical management of lung carcinoids.

An open-label, single-arm, phase 2 study of the Aurora kinase A inhibitor alisertib in patients with advanced urothelial cancer

BACKGROUND

Progress in developing effective salvage therapies for UC is warranted. Alisertib is an orally available, selective inhibitor of the aurora kinase A.

METHODS

A single-group, phase 2 trial was conducted with alisertib 50 mg orally BID for 7 days, with 14d rest until disease progression (PD) (NCT02109328). The primary endpoint (EP) was RECIST 1.1 objective response-rate (ORR, H0 ≤ 5%, H1 ≥ 20%, α = 10% and β = 20%). Eligibility included failure of at least one platinum-based regimen.

RESULTS

From 10/2014 to 04/2015, 22 patients were enrolled (20 evaluable for response), 8 (36.4%) in second-line and 14 (63.6 %) beyond the second-line. Eight (36.4%) had an ECOG-performance status 1-2. Two partial responses (PR, ORR: 9.1%), 7 stable disease (SD) and 11 PD were obtained. Median follow-up was 8.3 months (IQR: 7-10.3), 6-month progression-free survival (PFS) was 13.6% (95%CI: 4.8-39.0). Two SD are still receiving treatment after 11.5 and 6.3 months. Median overall survival (OS) was not reached (6-month OS: 59.1%, 95%CI: 41.7-83.7). Hb < 10 g/dl was significantly associated with shorter PFS and OS multivariably (p = 0.031 and p = 0.033). Tissue of the case with 11.5 month SD harbored a missense mutation of mTOR (E1813D), the nonsense mutation Q527STOP of TSC1, HER3 and TAF1L missense mutations. Grade 3-4 adverse events (AE) were: 40.9% mucositis, 36.4% fatigue, 18.2% neutropenia (13.6% febrile neutropenia). There were 2 treatment-related deaths.

CONCLUSIONS

The study did not meet the primary EP, yet sustained disease control was obtained in about 14% of patients. The incidence of AE and the issue of patient selection are two major concerns.

Pan-HER tyrosine-kinase inhibitors (TKI) dacomitinib and afatinib in penile squamous cell carcinoma (PSCC): Results from an ongoing open-label, single-group, phase 2 trial of dacomitinib in chemonaive patients (pts)

483

Background: Prognosis of pts with advanced/metastatic PSCC is poor and chemotherapy exerts a low efficacy. Targeting HER pathway is rational and promising in PSCC. Two companion trials are enrolling in the 1st-line/neoadjuvant setting (Dacomitinib, NCT01728233) and salvage setting (Afatinib, NCT02541903). Here we present the ongoing results of the former study. Dacomitinib is a potent, irreversible TKI of human EGFR/HER1, HER2 and HER4. Methods: 37 pts with clinical N2-3 or M1 disease receive oral Dacomitinib 45 mg daily until surgery or disease progression (PD)/unacceptable toxicity. No prior systemic therapy is allowed. Computed tomography and PET scan are repeated q2 months. Simon’s Optimal 2-stage design is applied. The primary endpoint is the objective response-rate (ORR = CR/PR according to RECIST v1.1: H0 ≤ 5%, H1 ≥ 20%, α and β = 10%). Next generation sequencing (NGS) with “Hot-spot cancer panel” (Ion Torrent, Life Technologies) is being performed for all enrolled pts. Results: From 06/13 to 05/15, 14 pts were treated. Median age was 57 yrs (IQR: 54-72). 4 had received inguinal/pelvic lymphadenectomy, 4 had inguinal+pelvic nodes, 10 bilateral disease, and 4 distant mets. Two pts achieved a PR (ORR: 14.3%), 8 a SD, 4 a PD. 8 pts (57.1%) had a metabolic PR. 9 pts underwent post-Dacomitinib lymphadenectomy: > 90% necrosis was seen in one patient. After a median follow-up of 6.97 months, 6 pts (42.8%) were progression-free (median PFS was 4.47 months). Median OS was 11.9 months, 1-year OS was 50% (95%CI: 8.05-82.63). Skin toxicity was observed in 7 pts (6 G1, 1 G3), G2 diarrhea in two, and bleeding of cutaneous mets in one. Tissue from one PR pt harbored missense mutations in FBXW7 (R505S), PTEN (A3T), and TP53 (R273H, loss of function mutation) genes. Conclusions: Dacomitinib is endowed with antitumor activity in PSCC. Results are pending confirmation in the whole sample size. Dacomitinib and Afatinib trials will provide insights into the targeting of HER pathway in PSCC based on prior chemotherapy administration. Preliminary data on molecular alterations linked to clinical benefit are being observed. Clinical trial information: NCT01728233.

A phase 2 study of the Aurora A kinase (AAK) tyrosine kinase inhibitor (TKI) alisertib (MLN8237) in patients (pts) with pretreated urothelial cancer (UC)

382

Background: Progress in developing effective salvage therapies for UC is warranted. AAK overexpression has been described in UC and spindle checkpoint (SC) dysregulation is a common feature. Alisertib is an orally available, selective TKI of AAK. Methods: A single-group, Ph2 trial was conducted with Alisertib 50 mg orally BID for 7 days, with 14d rest until disease progression (PD) (NCT01653028). The primary endpoint was RECIST 1.1 objective response-rate (ORR), and ≥ 3/20 responses were required (H0 ≤ 5%, H1 ≥ 20%, α = 5%/β = 20%) to move to a randomized trial of paclitaxel plus either Alisertib or placebo. Eligibility included failure of ≤ 2 platinum-based regimens. Cox regression analyses were done. Targeted sequencing of pts is being performed through the Ion AmpliSeq Comprehensive Cancer Panel (Life Technologies). Results: From 10/2014 to 04/2015, 22 pts were enrolled (20 evaluable for response), 8 (36.4%) in 2nd line and 14 (63.6%) > 2ndline. 8 (36.4%) had an ECOG-PS 1-2, 3 (13.6%) had Hb < 10mg/dl, 9 (40.9%) had liver metastases. 2 PR (ORR: 10%), 7 stable disease (SD) and 11 PD were recorded. Median FUP was 6.3 mos (IQR: 4.5-8.0). 6m-PFS was 18.2% (95%CI: 7.5-44.1), including 2 pts with 9.7 and 9.5 mos FUP (still ongoing, both > 2nd line). Median PFS was 1.8 mos (IQR: 1.3-3.4), but median OS was not reached (6m-OS: 63.6%, 95%CI: 46.4-87.3). Hb < 10gr/dl was significantly associated with shorter PFS and OS multivariably (p = 0.031 and p = 0.033). AAK-IHC expression did not correlate with outcome. Tissue of pt with 9.7 month SD harbored a missense mutation of mTOR (E1813D*) and the nonsense mutation Q527STOP* of TSC1, together with HER3 and TAF1Lmissense mutations. Grade 3-4 adverse events (AE) were: 54.5% alopecia, 41% mucositis, 36.4% fatigue, 18% neutropenia (14% febrile neutropenia). There were 2 treatment-related deaths (septic shock). Conclusions: Preliminary data suggest the possibility for sustained disease control in about 20% of pts, including very long term PR/SD. Hb ≥ 10 and mutations of TSC1/mTOR (TAF1L?) might be the clinical and biological markers for patient enrichment design with SC inhibitors like Alisertib, although the incidence of AE is a major concern. Clinical trial information: NCT01653028.

Screening with Low-Dose Computed Tomography Does Not Improve Survival of Small Cell Lung Cancer

INTRODUCTION

Small cell lung cancer (SCLC) constitutes a distinct component of symptomatic or advanced-stage lung cancers in clinical practice and in lung cancer screening trials. The purpose of this study was to describe the outcome of SCLC in lung cancer screening trials and compare the frequency of SCLC in our cohort with that in the major lung cancer screening trials.

METHODS

Subjects with a diagnosis of SCLC were selected from two lung cancer screening trials by low-dose computed tomography (LDCT), and their demographic characteristics, clinical parameters, tumor stage at diagnosis, therapy, and survival times were recorded. Survival curves were estimated using the Kaplan-Meier method.

RESULTS

Ten cases of SCLC were reported in 45,141 person-years (22 in 100,000 person-years), representing the 6% of all lung cancer cases. Cumulative tobacco consumption was 82 pack-years compared with 39 and 46 pack-years for the overall study population and subjects with non-SCLC, respectively. Most of the neoplasms were in an advanced stage (seven in stage IV and one each in stages IIIb, IIIa, and Ia). Two subjects were treated with lobectomy for curative purposes and died of diffuse metastasis within 2 years of diagnosis. The median overall survival time in the LDCT arms was 20.6 months, with no survivors remaining at 3 years.

CONCLUSIONS

Subjects in whom SCLC develops are a subgroup of smokers with extremely high cumulative tobacco consumption. Consequently, the frequency of SCLC in our population was lower than in other screening populations, with higher cumulative tobacco consumption. Screening for lung cancer by LDCT does not improve survival of SCLC, with no survivors remaining at 3 years after diagnosis.

Abstract LB-A08: ALK and ROS-1 status: A retrospective analysis in solid tumors

Background: Tyrosine kinase receptors are important regulators of cellular signal transduction pathways that play a crucial role in development of cancer. Among them, Anaplastic Lymphoma Kinase (ALK) and C-Ros Oncogene-1 (ROS-1) are activated by rearrangement in several tumors. Tailored therapies have been developed according to the status of ALK and ROS-1, successfully used in NSCLC and potentially useful in other solid tumors harboring ALK and ROS-1 aberrations.

Material and methods: ALK and ROS-1 status was evaluated in 666 and 441 patients with solid tumors, respectively, since 2014 at the Pathology Department. ALK and ROS-1 rearrangement and gene copy number variation (CNV) were assayed by fluorescence in situ hybridization (FISH). Gene copy number gain was defined by 3 to 5 fusion signals on average in ≥10% of cells, with amplification being highlighted by the clusters or 10 to 15 fusion signals in 10% or more tumor cells.

Results: ALK status was assessed in 650/666 (97%) cases, while ROS-1 status was evaluable in 426/441 (96%). We identified 15/650 (2.3%) cases with ALK rearrangment, including 13 lung adenocarcinomas (4.1%), 1 colon cancer (0.5%) and 1 myoepithelioma (0.5%). CNV for ALK was documented in 53% lung adenocarcinoma, 50% pancreatic, 41% biliary and 37% colon carcinoma patients. We found 7/426 (1.6%) tumors with ROS-1 rearrangement, corresponding to 5 lung (2.7%) and 2 colon (1.3%) adenocarcinomas. CNV for ROS-1 was more frequent in melanoma (77%), neuroendocrine tumors (39%) and NSCLC (32%, 3/4 cases of ROS-1 amplification were squamous carcinoma). Eight out of the 22 rearranged cases (5 ALK and 3 ROS-1) were tested for both genes: these aberrations were mutually exclusive. Three out of 5 (60%) ALK rearranged tumors showed ROS-1 deletion. No ALK and ROS-1 alterations were documented in 30 pancreatic, 25 H&N, 22 biliary tract, 13 renal, and 13 breast carcinomas, as well as in 13 melanomas and 36 other solid tumors.

Conclusions: ALK and ROS-1 rearrangement was found in 4.1% and 2.7% of NSCLC, respectively, in keeping with literature data. In other solid tumors, the percentage of rearrangements is exceedingly low, but melanoma, neuroendocrine tumors, pancreatic and colon cancer may show significant CNV. We speculate that such aberrations of ALK and ROS-1 could act as potential therapy targets, but additional investigation by immunohistochemistry and next generation sequencing is clinically warranted.

Citation Format: Maria Silvia Cona, matteo Duca, Adele Testi, Sara Cresta, Katia Fiorella Dotti, Alice Indini, Diego Signorelli, Giuseppe Pelosi, Filippo Guglielmo de Braud, Silvia Damian. ALK and ROS-1 status: A retrospective analysis in solid tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr LB-A08.

What clinicians are asking pathologists when dealing with lung neuroendocrine neoplasms?

Lung neuroendocrine tumors (NET) are currently classified in resection specimens according to four histological categories, namely typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Diagnostic criteria have remained unchanged in the 2015 WHO classification, which has ratified the wide acceptance and popularity of such terminology in the pathologists׳ and clinicians׳ community. A unifying umbrella of NE morphology and differentiation has been recognized in lung NET, which has pushed to enter an unique box of invasive tumors along with diffuse idiopathic pulmonary NE cell hyperplasia (DIPNECH) as a pre-invasive lesion with a potential toward the development of carcinoids. However, uncertainties remain in the terminology of lung NET upon small samples, where Ki-67 antigen could play some role to avoid misdiagnosing carcinoids as high-grade NE tumors. Epidemiologic, clinical and genetic traits support a biological three-tier over a pathology four-tier model, according to which TC are low malignancy tumors, AC intermediate malignancy tumors and LCNEC/SCC high malignancy tumors with no significant differences in survival among them. Inconsistencies in diagnostic reproducibility, troubles in the therapy of AC and LCNEC, and limitations to histology within the same tumor category argue in favor of a global re-thinking of lung NET where a grading system could play a role. This review outlines three main key questions in the field of lung NET: (A) unbiased diagnoses, (B) the role of Ki-67 and tumor grading, and (C) management of predictive markers. Answers are still inconclusive, thus additional research is required to improve our understanding on lung NET.

Conversion to stem-cell state in response to microenvironmental cues is regulated by balance between epithelial and mesenchymal features in lung cancer cells

Cancer cells within a tumor are functionally heterogeneous and specific subpopulations, defined as cancer initiating cells (CICs), are endowed with higher tumor forming potential. The CIC state, however, is not hierarchically stable and conversion of non‐CICs to CICs under microenvironment signals might represent a determinant of tumor aggressiveness. How plasticity is regulated at the cellular level is however poorly understood. To identify determinants of plasticity in lung cancer we exposed eight different cell lines to TGFβ1 to induce EMT and stimulate modulation of CD133+ CICs. We show that response to TGFβ1 treatment is heterogeneous with some cells readily switching to stem cell state (1.5–2 fold CICs increase) and others being unresponsive to stimulation. This response is unrelated to original CICs content or extent of EMT engagement but is tightly dependent on balance between epithelial and mesenchymal features as measured by the ratio of expression of CDH1 (E‐cadherin) to SNAI2. Epigenetic modulation of this balance can restore sensitivity of unresponsive models to microenvironmental stimuli, including those elicited by cancer‐associated fibroblasts both in vitro and in vivo. In particular, tumors with increased prevalence of cells with features of partial EMT (hybrid epithelial/mesenchymal phenotype) are endowed with the highest plasticity and specific patterns of expression of SNAI2 and CDH1 markers identify a subset of tumors with worse prognosis. In conclusion, here we describe a connection between a hybrid epithelial/mesenchymal phenotype and conversion to stem‐cell state in response to external stimuli. These findings have implications for current endeavors to identify tumors with increased plasticity.

Signals from the microenvironment are involved in modulation of cancer initiating cells (CICs) in lung cancer.

Balance between epithelial/mesenchymal features is a crucial determinant of proclivity to stemness phenotype acquisition.

Epigenetic modification of epithelial/mesenchymal balance can regulate response to microenvironmental stimuli.

A specific pattern of expression of E‐cadherin and SNAI2 is associated with worst prognosis in NSCLC.