ALK-positive adenocarcinoma of the lung expressing neuroendocrine markers and presenting as a "pituitary adenoma"

We report an ALK-rearranged adenocarcinoma of the lung presenting as a pituitary metastasis, clinically simulating a pituitary adenoma. The patient, a 50 year-old, former-smoking woman was admitted with a Parinaud's syndrome characterized by progressive oculomotor impairment of visual verticality, bitemporal hemianopsia and nystagmus. Imaging studies showed a sellar tumor and the biopsy revealed a TTF-1 and napsin positive lung adenocarcinoma strongly expressing synaptophysin and CD56, also harboring ALK rearrangement. A subsequent CT scan disclosed the primary lung mass of the left upper lobe. The patient progressed after 4 cycles of cisplatin/pemetrexed as first line treatment, but showed a partial response and a significant clinical benefit from the combination of ceritinib and nivolumab in a phase Ib trial. Despite its central nervous system tropism, ALK-rearranged adenocarcinoma manifesting with pituitary gland involvement was never reported. Second generation ALK inhibitors seem the best therapeutic strategy.

Primary resistance to osimertinib due to SCLC transformation: Issue of T790M determination on liquid re-biopsy

OBJECTIVES

EGFR T790M mutation is the most common mechanism of resistance to first-/second-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) and could be overcome by third-generation EGFR-TKIs, such as osimertinib. Liquid biopsy, a non-invasive technique used to test the presence of the resistant mutation, may help avoiding tissue re-biopsy. However, analysing only circulating-free DNA, information about other less frequent and coexisting resistance mechanisms may remain unrevealed.

MATERIALS AND METHODS

All patients reported in this series participated in the ASTRIS trial, a real world treatment study testing the efficacy of osimertinib (80mg os die) in advanced T790M-positive NSCLC progressed to prior EGFR-TKI. Patients were considered eligible to osimertinib if T790M positive on tissue or plasma samples. In our patients, EGFR molecular testing on blood sample was conducted with digital droplet PCR (ddPCR).

RESULTS

We report our experience of five patients treated with osimertinib after T790M detection on liquid biopsy that presented a disease progression at first tumor assessment mediated by SCLC transformation, as evidenced at tissue re-biopsies. All patients showed low ratio T790M/activating mutation in the blood before osimertinib (lower than 0.03). For three patients, EGFR mutational analysis was T790M-negative when re-assessed by using a less sensitive method (therascreen^®) on the same liquid biopsy sample analysed by ddPCR before osimertinib therapy.

CONCLUSION

Although liquid biopsy is a relevant tool to diagnose T790M presence in NSCLC patients resistant to EGFR-TKI, in case of a low ratio T790M/activating mutation, tissue biopsy should be considered to exclude the presence of SCLC transformation and/or other concomitant resistance mechanisms.

Does Immunohistochemistry Represent a Robust Alternative Technique in Determining Drugable Predictive Gene Alterations in Non-Small Cell Lung Cancer?

Immunohistochemistry (IHC) is a widely-tested, low-cost and rapid ancillary technique available in all laboratories of pathology. This method is generally used for diagnostic purposes, but several studies have investigated the sensitivity and specificity of different immunohistochemical antibodies as a surrogate test in the determination of predictive biomarkers in non-small cell lung cancer (NSCLC), particularly for Epidermal Growth Factor Receptor (EGFR) gene mutations, Anaplastic Lymphoma Kinase (ALK) gene and ROS1 rearrangements. In this review, a critical examination of the works comparing the consistency of IHC expression and conventional molecular techniques to identify genetic alterations with predictive value in NSCLC is discussed. Summarizing, data on sensitivity and specificity of antibodies against ALK and ROS1 are very consistent and time has come to trust in IHC at least as a cost-effective screening tool to identify patients with rearranged tumors in clinical practice. On the other hand, mutant-specific antibodies against EGFR demonstrate a good specificity but a lowto- fair sensitivity, raising some cautions on their employment as robust predictive biomarkers. A brief comment on preliminary experiences with antibodies against BRAF, RET, HER2 and c-MET is also included.

Secondary biopsy of non-oncogenic-driven lung cancer may reveal a clinically sensible histologic change. A brief report of two paradigmatic cases

After an initial benefit, non-small-cell lung cancer (NSCLC) patients receiving therapy with tyrosine kinase inhibitors develop drug resistance through a variety of mechanisms. Among these, tumor histology changes are a mechanism of acquired resistance in epidermal growth factor receptor-mutated and anaplastic lymphoma kinase-rearranged NSCLC cases. The current availability of therapeutic approaches to overcome tyrosine kinase inhibitor resistance in oncogenic-driven lung cancers justifies secondary tumor biopsy in these patients. On the other hand, little is known about the mechanism of disease progression in non-oncogenic driven NSCLC. Nevertheless, NSCLC lacking "druggable" genetic alterations are not considered for secondary biopsy, as it is commonly believed that these tumors cannot develop histologic or molecular changes. Herein, we report two paradigmatic cases of wild-type NSCLC showing histologic "change" on secondary biopsy, allowing for a successful switch in therapeutic strategy.

Analysis of a panel of druggable gene mutations and of ALK and PD-L1 expression in a series of thymic epithelial tumors (TETs)

INTRODUCTION

Thymic epithelial tumors (TETs) are rare neoplasms with different prognosis lacking consistent molecular alterations possibly leading to targeted therapy. We collected a consecutive series of TETs aimed at investigating the mutational status of druggable genes (EGFR, c-KIT, KRAS, BRAF, PDGFR-alpha and -beta, HER2 and c-MET) and the expression of ALK and PD-L1.

PATIENTS AND METHODS

One hundred twelve consecutive cases of TETs and relative clinico-pathologic features were collected. Immunohistochemical expression of ALK (clone D5F3) and PD-L1 (clone E1L3N), molecular analysis of EGFR (exons 18-21), c-KIT (exons 9,11,13,14,17), KRAS (exon 2), BRAF (exon 15), PDGFR-alpha (exon 12) and -beta (exons 12, 14, 18), HER-2 (exons 19 and 20) and c-MET (exons 14, 17, 18, 19) mutations were performed. Immuno-molecular results were then statistically matched with clinico-pathologic characteristics.

RESULTS

Patients were male in 54% of cases, with a median age of 61 years (range 19-83) and affected mainly by thymoma (78%) in stage II (45%). At molecular analysis, there were 4 c-KIT mutations (occurring in exon 11 V559A, L576P, Y553N and exon 17 D820E) in thymic carcinomas (typeC), but not in other tumor types (p=0.003). No mutations were detected in other genes and none case was ALK positive. Twenty-nine (26%) cases were PD-L1 positive (65% of thymic carcinomas and 18% of thymomas). High PD-L1 expression was statistically associated with WHO classification stage type C (p<0.001) and Masaoka stage III-IV disease (p=0.007). In univariate analysis, WHO classification type C, advanced Masaoka stage and absence of myasthenia, but not PD-L1 expressions were correlated with worse survival; at multivariate analysis, only WHO type C confirmed its negative prognostic role.

CONCLUSION

A subset of TETs as thymic carcinomas can harbor c-KIT mutations and elevated PD-L1 expression that could represent targets of potential therapeutic use.

Diamond: immunohistochemistry versus sequencing in EGFR analysis of lung adenocarcinomas

AIMS

Identification of epidermal growth factor receptor (EGFR) mutations in lung adenocarcinomas is the single most important predictor of clinical response and outcome using EGFR tyrosine kinase inhibitors (TKIs). EGFR E746-A750del and L858R mutations are the most common gene alterations, also predicting the best clinical response to TKIs. We evaluated the accuracy of EGFR mutation-specific antibodies in a large cohort of lung adenocarcinomas, with different molecular settings and types of tissue samples.

METHODS

300 lung adenocarcinomas diagnosed on cytology (48 cell blocks), biopsy (157 cases) and surgical resections (95 cases) were selected. All cases were investigated for EGFR by sequencing and two mutation-specific antibodies (clone 6B6 for E746-A750del; clone 43B2 for L858R) were tested using an automated immunostainer. Discordant results were investigated by next-generation sequencing (NGS).

RESULTS

Overall sensitivity and specificity of mutant-specific antibodies were 58.6% and 98.0%, respectively, and they increased up to 84% and 100% if only tumours harbouring E746-A750del were considered. In 13 discordant cases, NGS confirmed immunohistochemistry results in eight samples.

CONCLUSIONS

The EGFR mutation-specific antibodies have a fair/good sensitivity and good/high specificity in identifying classic mutations, but they cannot replace molecular tests. The antibodies work equally well on biopsies and cell blocks, possibly permitting a rapid screening in cases with poor material.

BE-POSITIVE: Beyond progression after tyrosine kinase inhibitor in EGFR- positive non small cell lung cancer patients: Results from a multicenter Italian observational study

OBJECTIVES

Non-small-cell-lung-cancer (NSCLC) patients harbouring epidermal growth factor receptor (EGFR) mutations develop drug resistance after 9-12 months of EGFR tyrosine kinase inhibitors (TKIs) therapy pointing out the issue of the second-line treatment choice.

MATERIALS AND METHODS

From June 2009 until May 2013 patients affected by advanced NSCLC harbouring EGFR mutations receiving first-line TKI were collected mainly retrospectively in 24 Italian Centers. Primary objective was to describe the percentage of EGFR mutated patients receiving second-line therapy after progression to first-line EGFR-TKIs assessing the type, the activity in terms of objective response rate (ORR), efficacy in terms of progression free survival (PFS) and overall survival (OS), and safety of second-line treatment. Secondary objective was to describe the efficacy of first-line EGFR-TKIs.

RESULTS

312 patients were included. Most of them were females (203, 65.1%), never smokers (200, 64.1%), with adenocarcinoma histology (290, 92.9%). The most common mutations were EGFR exon 19 deletion and L858R, detected in 186 and 97 cases (59.6% and 31.1%), respectively. At data cut-off, 274 patients (95.1%) received any second-line treatment (including best supportive care or local treatments only). A total of 163 patients received second-line systemic therapy with an ORR of 20.9% (95% CI:14.62-27.10), a median PFS and OS of 4.7 (95% CI:3.81-5.26) and 24.5 (95% CI:21.65-27.37) months, respectively. Grade 3-4 hematological and non-hematological toxicities were reported in 9% and 6.3% of 144 patients treated with chemotherapy while non-hematological toxicity was reported in 4 cases of the 17 patients receiving second-line target agents.

CONCLUSIONS

BE-Positive is the first multicenter observational study reporting outcomes of therapies in a "real-life Caucasian EGFR-mutated population", highlighting the need of further researches about new treatment strategies in this setting.

Squamous Cell Carcinoma "Transformation" Concurrent with Secondary T790M Mutation in Resistant EGFR-Mutated Adenocarcinomas

The authors report two cases of epidermal growth factor receptor gene (EGFR)-mutant stage IV lung adenocarcinomas developing immunohistochemically proven squamous cell carcinoma (SCC) "transformation" concurrently with T790M EGFR mutation, leading to acquired resistance to EGFR inhibitors. Moreover, the histologic change of EGFR-mutant lung adenocarcinoma into SCC has been recently reported in literature. The histological transformation to SCC appears as a novel mechanism of acquired EGFR TKI resistance in EGFR-mutated adenocarcinomas and it may be challenging for treatment.