Deepening the Knowledge of ROS1 Rearrangements in Non-Small Cell Lung Cancer: Diagnosis, Treatment, Resistance and Concomitant Alterations

ROS proto-oncogene 1 (ROS1) rearrangements are reported in about 1-2% of non-squamous non-small-cell lung cancer (NSCLC). After efficacy of crizotinib was demonstrated, identification of ROS1 translocations in advanced disease became fundamental to give patients the chance of specific and effective treatment. Different methods are available for detection of rearrangements, and probably the real prevalence of ROS1 rearrangements is higher than that reported in literature, as our capacity to detect gene rearrangements is improving. In particular, with next generation sequencing (NGS) techniques, we are currently able to assess multiple genes simultaneously with increasing sensitivity. This is leading to overcome the "single oncogenic driver" paradigm, and in the very near future, the co-existence of multiple drivers will probably emerge more frequently and represent a therapeutic issue. Since recently, crizotinib has been the only available therapy, but today, many other tyrosine kinase inhibitors (TKI) are emerging and seem promising both in first and subsequent lines of treatment. Indeed, novel inhibitors are also able to overcome resistance mutations to crizotinib, hypothesizing a possible sequential strategy also in ROS1-rearranged disease. In this review, we will focus on ROS1 rearrangements, dealing with diagnostic aspects, new therapeutic options, resistance issues and the coexistence of ROS1 translocations with other molecular alterations.

Anaplastic Lymphoma Kinase (ALK)-positive Tumors: Clinical, Radiographic and Molecular Profiles, and Uncommon Sites of Metastases in Patients With Lung Adenocarcinoma

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene rearrangements are observed in about 4% to 8% non-small cell lung cancer (NSCLC). ALK+ tumors have been associated with increased pleural and pericardial disease. Our primary objective was to determine the uncommon sites of metastasis of ALK+ NSCLC. Secondary objectives included study of coexisting mutations and factors impacting survival of ALK+ NSCLC.

METHODS

All patients with metastatic ALK+ NSCLC at the City of Hope Cancer Center in Duarte, California from 2010 to 2017 were selected for retrospective chart review. The demographic variables were collected. The molecular statuses of patients were evaluated through commercially available platforms for next-generation sequencing. Three-dimensional volumetric images were generated for the primary lesion and different sites of metastasis.

RESULTS

Sixty two patients with ALK+ NSCLC were identified from 2010 to 2017. The median age was 59 with 36 (58%) female individuals and only 20 (32%) smokers. Twenty four patients had uncommon sites of metastasis which were thyroid, soft tissue, chest and abdominal wall, spleen, peritoneum, omentum, kidney, and ovary. Common characteristics of the primary lesions were right upper lobe location (N=23 [37%]), oval shape (N=22 [35%]), irregular margins (N=26 [42%]), solid lesions (N=27 [44%]), presence of pleural contact or effusion (N=22 [35%]). Twenty four patients had next-generation sequencing testing which showed coexisting mutations such as TP53 (N=8), EGFR (N=5), KRAS (N=3). Patients with uncommon sites of metastasis had a decreased median survival compared with common sites (39 vs. 82 m, P=0.046).

CONCLUSION

In NSCLC, ALK rearrangements may not be mutually exclusive mutations and can present with unique radiographic patterns. Patients with uncommon sites of metastasis may have worse outcomes.

Analysis of Genetic Alterations in Tunisian Patients with Lung Adenocarcinoma

The identification of the mutations that drive lung cancer have furnished new targets for the treatment of non-small cell lung cancer (NSCLC) and led to the development of targeted therapies such as tyrosine kinase inhibitors that are used to combat the molecular changes promoting cancer progression. Furthermore, biomarkers identified from gene analysis can be used to detect early lung cancer, determine patient prognosis, and monitor response to therapy. In the present study we analyzed the molecular profile of seventy-three Tunisian patients with lung adenocarcinoma (LAD). Mutational analyses for EGFR and KRAS were performed using direct sequencing, immunohistochemistry or MassARRAY. Anaplastic lymphoma kinase (ALK) rearrangement was evaluated by immunohistochemistry using the D5F3 clone, and p53 expression was also assessed. The median age of patients at diagnosis was 61 years (range 23-82 years). Using different methodologies, EGFR mutations were found in 5.47% of patients and only exon 19 deletions "E746-A750 del" were detected. KRAS mutations were present in 9.58% of cases, while only one patient was ALK-positive. Moreover, abnormal immunostaining of p53 was detected in 56.16% of patients. In conclusion, the detected rates of EGFR and KRAS mutation and ALK rearrangement were lower than those found in European and Asian countries, whereas, abnormal p53 expression was slightly more frequent. Furthermore, given the small sample size of this study, a more comprehensive analysis of this patient set is warranted.

Coexistence of EGFR, KRAS, BRAF, and PIK3CA Mutations and ALK Rearrangement in a Comprehensive Cohort of 326 Consecutive Spanish Nonsquamous NSCLC Patients

INTRODUCTION

Molecular screening is crucial for the care of nonsquamous non-small-cell lung cancer (NSCLC) patients. The coexistence of mutations could have important consequences regarding treatment. We described the mutational patterns and coexistence among patients and their outcomes after targeted treatment.

MATERIALS AND METHODS

Data from consecutive patients with newly diagnosed nonsquamous NSCLC were prospectively collected. Next-generation sequencing analysis of mutational hotspots in the EGFR, KRAS, PIK3CA, and BRAF genes and analysis of anaplastic lymphoma kinase (ALK) rearrangement were performed.

RESULTS

A total of 326 patients with nonsquamous NSCLC were identified. Of the 326 patients, 240 (73.6%) had EGFR, 141 (43.3%) KRAS, 137 (42.0%) BRAF, 130 (39.9%) PIK3CA mutation and 148 (45.4%) ALK rearrangement determined. Of the 240 with EGFR determination, 24.1% harbored EGFR mutations. Of these, 16.3% were activating mutations (43.6%, exon 19 deletion; 46.1%, exon 21; and 10.3%, exon 18) and 7.9% were nonsensitizing EGFR mutations. Furthermore, 39.0% had KRAS mutations, 2.9% BRAF mutations, 10.0% PIK3CA mutations, and 8.8% ALK rearrangements. Of the 154 stage IV patients with ≥ 1 mutations, analysis showed 19 coexisting cases (12.3%). Of 8 patients receiving targeted treatment, 6 had no response. Both responders to targeted treatment had coexistent PIK3CA mutations.

CONCLUSION

Driver mutations can coexist in nonsquamous NSCLC. In our cohort, 12.3% of cases with stage IV disease had multiple mutations. Targeted treatment might not be as effective in patients with coexisting mutations; however, coexistence with PIK3CA might not preclude a response.

Concomitant EML4-ALK rearrangement and EGFR mutation in non-small cell lung cancer patients: a literature review of 100 cases

The discovery of EGFR mutations and EML4-ALK gene rearrangements has radically changed the therapeutic scenario for patients with advanced non-small cell lung cancer. ALK and EGFR tyrosine-kinase inhibitors showed better activity and efficacy than standard chemotherapy in the first and second line treatment settings, leading to a clear advantage in overall survival of advanced non-small cell lung cancer patients harboring these genetic alterations.

Historically the coexistence of EGFR mutations and EML4-ALK rearrangements in the same tumor has been described as virtually impossible. Nevertheless many recent observations seem to show that it is not true in all cases.

In this review we will discuss the available literature data regarding this rare group of patients in order to give some suggestions useful for their clinical management. Furthermore we report here two cases of concomitant presence of both alterations that will help us in the development of discussion.

High Prevalence of Concomitant Oncogene Mutations in Prospectively Identified Patients with ROS1-Positive Metastatic Lung Cancer

OBJECTIVES

Chromosomal rearrangements involving ROS1 define a rare entity of lung adenocarcinomas with exquisite sensitivity to molecularly targeted therapy. We report clinical outcomes and genomic findings of patients with ROS1-positive lung cancer who were prospectively identified within a multiplex biomarker profiling program at the West German Cancer Center.

METHODS

Standardized immunohistochemical (IHC) analysis, fluorescence in situ hybridization (FISH), and hotspot mutation analyses were performed in 1345 patients with advanced cancer, including 805 patients with metastatic lung adenocarcinoma. Clinical and epidemiological data were retrieved from the institutional database.

RESULTS

ROS1 positivity by IHC analysis was detected in 25 patients with lung cancer (4.8% of lung adenocarcinomas), including 13 patients (2.5%) with ROS1 FISH positivity with a cutoff of at least 15% of events. Of the ROS1 IHC analysis-positive cases, 36% presented with concomitant oncogenic driver mutations involving EGFR (six cases, five of which were clinically validated by response to EGFR-targeting agents), KRAS (two cases), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA), and BRAF. Three cases initially classified as ROS1 FISH-negative passed the threshold of 15% positive events when repeat biopsies were analyzed at progression. The median overall survival of the ROS1-positive patients (104 months) was significantly superior to that of the 261 patients with EGFR/anaplastic lymphoma kinase/ROS1-negative lung adenocarcinoma (24.4 months, p = 0.044). Interestingly, the overall survival of the 13 ROS1-positive patients with lung cancer from initiation of pemetrexed-based chemotherapy was significantly prolonged when compared with that of 169 pemetrexed-treated patients with EGFR/anaplastic lymphoma kinase/ROS1-negative adenocarcinoma (p = 0.01).

CONCLUSIONS

ROS1-positive metastatic lung adenocarcinomas frequently harbor concomitant oncogenic driver mutations. Levels of ROS1 FISH-positive events are variable over time. This heterogeneity provides additional therapeutic options if discovered by multiplex biomarker testing and repeat biopsies.

Profile of Ventana ALK (D5F3) companion diagnostic assay for non-small-cell lung carcinomas

The development of several ALK inhibitors means that the importance of accurately identifying ALK-positive lung cancer has never been greater. Therefore, it is crucial that ALK testing assays become more standardized. The aim of this review is to comment on the recently FDA-approved VENTANA ALK (D5F3) Companion Diagnostic (CDx) Assay. This kit provides high sensitivity and specificity for the detection of ALK rearrangements and seamless integration into the laboratory workflow, with a fully automated analytical phase and fast interpretation. The use of controls increases the sensitivity and specificity and a dichotomous scoring approach enhances reproducibility.

Nonsquamous, Non-Small-Cell Lung Cancer Patients Who Carry a Double Mutation of EGFR, EML4-ALK or KRAS: Frequency, Clinical-Pathological Characteristics, and Response to Therapy

BACKGROUND

Epidermal growth factor receptor (EGFR) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations, and echinoderm microtubule-associated protein-like 4 (EML4) anaplastic lymphoma kinase (ALK) translocation are generally considered to be mutually exclusive. However, concomitant mutations are found in a small number of patients and the effect of these on response to targeted therapy is still unknown.

PATIENTS AND METHODS

We considered 380 non-small-cell lung cancer (NSCLC) patients who underwent nonsequential testing for EGFR and EML4-ALK translocation. KRAS mutation analysis was also performed on 282 patients.

RESULTS

We found 1.6%, 1.1%, and 2.5% of patients who showed a double mutation comprising EGFR and EML4-ALK, EGFR and KRAS, and EML4-ALK and KRAS, respectively. Twenty-eight patients with EGFR mutation underwent first-line therapy with a tyrosine kinase receptor; a clinical benefit was observed in 81.8% of patients with EGFR mutations only and in 67% of those who also showed an EML4-ALK translocation. Twelve patients with an EML4-ALK translocation received crizotinib and 7 of these had disease progression within 3 months (2 had a concomitant KRAS mutation and 1 had a concomitant EGFR mutation). Two patients showed stable disease, 1 of whom also had a KRAS mutation. Two patients obtained a partial response and 1 had a complete response; all harbored an EML4-ALK translocation only. The median overall survival of patients who carried an EML4-ALK translocation alone or concomitant with a KRAS mutation was 57.1 (range, 10.7-not reached) and 10.7 (range, 4.6-not reached) months, respectively.

CONCLUSION

Concomitant EGFR, EML4-ALK, or KRAS mutations can occur in NSCLC. Concomitant KRAS mutation and EML4-ALK translocation represents the most common double alteration and confers a poor prognosis.

EGFR and KRAS Mutations in ALK-Positive Lung Adenocarcinomas: Biological and Clinical Effect

INTRODUCTION

In lung adenocarcinoma (ADC), anaplastic lymphoma receptor tyrosine kinase (ALK) rearrangements are mutually exclusive with epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. However, the existence of double-positive (DP) patients have been sporadically described. We identified DP cases in therapy-naive ALK-rearranged ADC and characterized the biology of these tumors to better understand the clinical response to tyrosine kinase inhibitors (TKIs).

MATERIALS AND METHODS

We selected 42 ALK-positive ADCs from a multicentric series of 301 cases of ADCs. A mutational analysis was performed using Sanger and/or pyrosequencing to address exons 18-21 of EGFR and codons 12-13 of the KRAS gene. In addition, the KRAS and EGFR copy number was investigated using fluorescent in situ hybridization. DP patients were treated with TKIs, and their response was evaluated according to the Response Evaluation Criteria in Solid Tumors criteria.

RESULTS

Eight of 42 ALK-positive ADCs (19%) demonstrated a concomitant mutation in the EGFR (3 cases) or KRAS (5 cases) genes and were classified as DP. All DP cases displayed copy number gains in the EGFR or KRAS gene because of polysomy or gene amplification. In the latter cases, a mutant allele-specific imbalance was observed. Four patients were treated with TKIs. The 2 EGFR-mutant DP patients demonstrated a better response to crizotinib compared with erlotinib. The 2 KRAS-mutant DP patients experienced opposite responses to crizotinib.

CONCLUSION

The incidence of DP ADC is not negligible. Patients with ALK/EGFR might benefit more from crizotinib compared with erlotinib administration, although the efficacy of TKIs in patients with ALK/KRAS remains unclear. An integrated targeted therapy should be considered for patients with DP ADC.