Updated Results of a Global Phase II Study with Crizotinib in Advanced Alk-Positive Non-Small Cell Lung Cancer (NSCLC)

ALK inhibitors in cancer: mechanisms of resistance and therapeutic management strategies

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified as potent oncogenic drivers in several malignancies, including non-small cell lung cancer (NSCLC). The discovery of ALK inhibition using a tyrosine kinase inhibitor (TKI) has dramatically improved the outcomes of patients with ALK-mutated NSCLC. However, the emergence of intrinsic and acquired resistance inevitably occurs with ALK TKI use. This review describes the molecular mechanisms of ALK TKI resistance and discusses management strategies to overcome therapeutic resistance.

Targeted Therapy for Cancers: From Ongoing Clinical Trials to FDA-Approved Drugs

The development of targeted therapies has revolutionized cancer treatment, offering improved efficacy with reduced side effects compared with traditional chemotherapy. This review highlights the current landscape of targeted therapy in lung cancer, colorectal cancer, and prostate cancer, focusing on key molecular targets. Moreover, it aligns with US Food and Drug Administration (FDA)-approved drugs and drug candidates. In lung cancer, mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) gene rearrangements have emerged as significant targets. FDA-approved drugs like osimertinib and crizotinib specifically inhibit these aberrant pathways, providing remarkable benefits in patients with EGFR-mutated or ALK-positive lung cancer. Colorectal cancer treatment has been shaped by targeting the vascular endothelial growth factor (VEGF) and EGFR. Bevacizumab and cetuximab are prominent FDA-approved agents that hinder VEGF and EGFR signaling, significantly enhancing outcomes in metastatic colorectal cancer patients. In prostate cancer, androgen receptor (AR) targeting is pivotal. Drugs like enzalutamide, apalutamide, and darolutamide effectively inhibit AR signaling, demonstrating efficacy in castration-resistant prostate cancer. This review further highlights promising targets like mesenchymal-epithelial transition (MET), ROS1, BRAF, and poly(ADP-ribose) polymeras (PARP) in specific cancer subsets, along with ongoing clinical trials that continue to shape the future of targeted therapy.

Development of HPLC-MS/MS assay for quantitation of ensartinib in human plasma and its application to a pharmacokinetics study in Chinese patients

Ensartinib is a novel anaplastic lymphoma kinase (ALK) inhibitor with potent activity against a broad range of known crizotinib-resistant ALK mutations and is developed to treat patients with non-small-cell lung cancer. This study was the first to develop and validate a rapid and sensitive HPLC-MS/MS method for the determination of ensartinib in human plasma. The plasma samples were extracted using liquid extraction, and chromatographic separation was performed using a Phenomenex, Luna phenyl-hexyl column (50 × 2.0 mm, 5 μm). Electrospray ionization in positive-ion mode and multiple reaction monitoring were used to monitor ion transitions at m/z 561.3 → 257.1 (ensartinib) and 565.2 → 261.2 (internal standard: X-396-d4), respectively. The method yielded excellent linearity in the range of 0.5-500 ng/ml with the lowest quantification of 0.5 ng/ml. Both intra- and inter-run precisions (relative standard deviation %) were less than 15%, with accuracy (relative error %) between ±15%. Extraction recovery, matrix effect, selectivity, and stability were also validated and found to be satisfactory. Finally, the validated method was successfully applied in a phase I clinical study of ensartinib in Chinese subjects with advanced ALK-positive non-small-cell lung cancer.

Renal complication of crizotinib: Crizotinib-associated complex renal cyst

Crizotinib is one of the first generations of tyrosine kinase inhibitors targeting anaplastic lymphoma kinase(ALK) and is recently found to be associated with the development of complex renal cysts with inconclusive explanation up to this time. Hereby, we discuss the hypothesis of Crizotinib-associated complex renal cyst development and coexisting renal impairment after initiation of the treatment in a 75-year-old man with ALK-positive non-small cell lung cancer whose complex renal cysts evolved after initiation and cessation of Crizotinib treatment. The coexistence as renal impairment persisted even after switching from Crizotinib to Ceritinib.

Ovarian metastasis from lung adenocarcinoma with ALK-positive rearrangement detected by next generation sequencing: A case report and literatures review

Ovarian metastasis is an exceptionally rare condition in lung adenocarcinoma patients and is often difficult to distinguish from primary ovarian carcinoma. ALK (anaplastic lymphoma kinase) tyrosine kinase inhibitors elicit a significant objective response rate and are well-tolerated in advanced ALK-positive lung cancer. Hence, we report a case of a 41-year-old woman with ovarian metastases from NSCLC. After receiving a 6 course first line chemotherapy and 8 course maintenance therapy, the patient suffered acute abdominal pain, so surgery was performed. ALK rearrangement was detected by next generation sequencing, with a 13% abundance of ALK fusion. Crizotinib was administered, and the disease remained stable after 10 months of crizotinib therapy. Further, we reviewed the literature related to characteristics of metastatic ovarian malignancies that form from lung tumors, the utility of ALK inhibition for treating ALK-positive NSCLC, the molecular diagnosis of ALK rearrangement and the role of next generation sequencing for ALK rearrangement detection.

Unveiling changes in the landscape of patient populations in cancer early drug development

The introduction of new Molecularly Targeted Agents (MTA) has changed the landscape in Early Drug Development (EDD) over the last two decades, leading to an improvement in clinical trial design. Previous Phase 1 (Ph1) studies with cytotoxics focused on safety objectives, only recruiting heavily pre-treated cancer patients, have been left behind. In this review, we will illustrate the slow although unstoppable change that has increasingly been observed in those populations candidate to participate in EDD trials with the advent of MTA. As more evidence regarding oncogene addiction becomes available, molecular-biomarker driven selection has been implemented among Molecularly-Selected Population (MSP) studies. New Window-Of-Opportunity (WOO) and Phase 0 (Ph0) studies have been developed in order to assess whether a MTA produces the hypothetical proposed biological effect. The rising need of getting early pharmacokinetics and pharmacodynamics data has led to the conduction of Healthy Volunteer (HV) studies, in part favoured for the particular and different toxicity profile of these MTA. However, several challenges will need to be addressed in order to boost the implementation of these new clinical trial designs in the forthcoming years. Among the problems to overcome, we would highlight a better coordination effort between centers for ensuring adequate patient accrual among small patient populations and a deepening into the ethics implied in enrolling patients in studies with no therapeutic intent. However, these tribulations will be certainly compensated by the possibility of opening a new horizon of treatment for diseases with dismal prognosis.

New Treatment Options for ALK-Rearranged Non-Small Cell Lung Cancer

OPINION STATEMENT

ALK rearrangements are present in 3-5% of patients with non-small cell lung cancer (NSCLC) and after epidermal growth factor receptor (EGFR) mutations represent the second molecular target in NSCLC to be validated through phase III clinical trials. The PROFILE 1014 international multicentre phase III trial demonstrated the superiority of crizotinib over standard chemotherapy, establishing crizotinib as standard first-line therapy for patients with advanced ALK-positive NSCLC and indicating the requirement for ALK testing to guide selection of optimal first-line therapy for non-squamous NSCLC. Despite impressive and durable responses, progression on treatment reflecting the development of acquired resistance is inevitable. There are several mechanisms of resistance including ALK kinase mutation or copy number gain, activation of bypass pathways and potentially pharmacokinetic failure of therapy (most commonly in CNS). A broad array of newer generation ALK inhibitors are in development that appear effective in the crizotinib-resistant setting including in patients with intracranial progression. These agents, including ceritinib and alectinib, have a higher potency against ALK kinase than crizotinib, activity against mutations that confer resistance to crizotinib and potentially improved CNS penetration. While in selected patients, continued therapy with crizotinib after local ablative treatments of oligo-progressive systemic or CNS disease may be an option, for many patients use of a newer generation compound will be effective. First-line treatment with newer generation ALK inhibitors may have potential advantages over sequential treatment after crizotinib; however, the optimal sequence of therapy with ALK inhibitors has not been determined and is being explored in ongoing phase III studies.

Alectinib for ALK-positive non-small-cell lung cancer

INTRODUCTION

Anaplastic lymphoma kinase (ALK) rearrangements are present in about 5% of advanced non-small-cell lung cancer (NSCLC) patients. Despite the initial response, after a median of 1-2 years, ALK-positive patients developed an acquired resistance to the ALK-inhibitor crizotinib. Among the most promising second-generation ALK-inhibitors, alectinib is being investigated in crizotinib-naïve and -resistant ALK-positive NSCLC patients.

AREAS COVERED

The current state-of-the-art of ALK-inhibitors treatment, and in particular the role of alectinib in this setting, is reviewed and discussed. A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question was undertaken. Expert commentary: Alectinib reports promising results with a good safety profile, becoming a potentially very important option for ALK-translocated NSCLC patients. The preliminary results from the J-ALEX phase III randomized trial performed in ALK-rearranged NSCLC Japanese patients showed a better activity and tolerability of alectinib versus crizotinib.

Role of anaplastic lymphoma kinase inhibition in the treatment of non-small-cell lung cancer

PURPOSE

Published data on the clinical efficacy, safety, dosage and administration, and costs of the anaplastic lymphoma kinase (ALK) inhibitors crizotinib and ceritinib in the treatment of non-small-cell lung cancer (NSCLC) are reviewed and compared.

SUMMARY

The ALK protein functions as a transmembrane receptor tyrosine kinase; rearrangements of the ALK gene are associated with the development of NSCLC with adenocarcinoma histology. Crizotinib is an oral tyrosine kinase inhibitor approved in 2011 as a first-line therapy for patients with metastatic ALK mutation-driven NSCLC. Significantly improved response rates and progression-free survival (PFS) have been reported with the use of crizotinib therapy versus standard chemotherapy, but mutations conferring resistance to treatment develop in most cases. The second-generation ALK inhibitor ceritinib was approved in 2014 for the treatment of ALK-mutated NSCLC in patients who are intolerant or develop resistance to crizotinib. In a clinical trial of ceritinib involving 130 patients with ALK-positive NSCLC, the majority of whom had experienced disease progression during crizotinib use, patients receiving at least 400 mg of ceritinib daily had an overall response rate of 56% and median PFS of seven months. Adverse effects commonly reported with the use of either drug include visual disturbances, gastrointestinal disorders (e.g., diarrhea), and liver enzyme abnormalities.

CONCLUSION

The tyrosine kinase inhibitors crizotinib and ceritinib provide an effective treatment approach for patients with ALK-mutated NSCLC. Efficacy data for both crizotinib and ceritinib indicate improved response rates and PFS with the use of either drug as an alternative to standard chemotherapy.

Anaplastic Lymphoma Kinase Variants and the Percentage of ALK-Positive Tumor Cells and the Efficacy of Crizotinib in Advanced NSCLC

BACKGROUND

Anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer patients exhibited heterogeneous magnitude of response and duration time to criztotinib treatment. This study explored ALK variants and the percentage of ALK-positive cells using fluorescent in situ hybridization (FISH) on clinical efficacy of crizotinib.

PATIENTS AND METHODS

A total of 120 patients with ALK rearrangement who were treated with criztotinib were enrolled. ALK variants were clarified in 61 patients, and ALK percentages were evaluated using FISH in 114 ALK-positive patients. Retrospectively, objective response rate, and progression-free survival (PFS) were evaluated.

RESULTS

A total of 61 patients with specific ALK variants were divided into 3 subgroups, echinoderm microtubule-associated protein like 4 (EML4)-ALK variant 1 (n = 22), EML4-ALK variant 3a/b (n = 18), and other ALK variants (n = 21). Median PFS in the 3 subgroups was 11.0 months (95% confidence interval [CI], 5.5-16.5), 10.9 months (95% CI, 5.9-15.8), 7.4 months (95% CI, 3.2-11.6), respectively, and no significant difference (P = .795) existed among them. The percentage of ALK-positive cells in FISH analysis was weakly correlated with PFS (rs = 0.235; P = .015). Additionally, it was also weakly correlated with best response to crizotinib (rs = 0.288; P = .003). Overall, there were 45, 49, and 26 patients receiving first, second, and third or further-line crizotinib, respectively. Median PFS in the first-line setting (10.5 months; 95% CI, 8.6-12.4) was significantly longer than that in the second-line setting (8.3 months; 95% CI, 4.7-12.0; P = .020).

CONCLUSION

Anaplastic lymphoma kinase variants might have no correlation with clinical response to crizotinib. The percentage of ALK-positive cells might correlate with the extent of benefit from crizotinib treatment.

Cross-over-it's a feature, not a bug

Pharmaceutical companies, investigators, regulators, and payers need to work together to adapt standards for drug development that meet the needs of all stakeholders, but first and foremost, benefit cancer patients in the most appropriate way.

Future options for ALK-positive non-small cell lung cancer

Recent advances in the understanding of non-small cell lung cancer (NSCLC) biology have revealed a number of 'targetable' genetic alterations that underlie cancer growth and survival in specific patients subgroups. The anaplastic lymphoma kinase (ALK) gene rearrangement identifies a population of NSCLCs in whom dysregulation of ALK-tyrosine kinase (-TK) leads to uncontrolled proliferation of cancer cells, thus providing the basis for the therapeutic use of ALK-TK inhibitors (-TKIs) in ALK-rearranged (-positive) disease. Crizotinib was the first ALK-TKI to undergo clinical development in ALK-positive advanced NSCLC, in which it has been shown to greatly outperform the best available chemotherapy regimen in either second- or first-line setting. More recently, the novel second-generation ALK-TKI ceritinib has been shown to be highly active in either crizotinib-pretreated or -naïve population. Nevertheless, as mechanisms of resistance to crizotinib and ALK-TKIs in general are being progressively elucidated, the treatment landscape of ALK-positive NSCLC is expected to evolve rapidly. In the present review we will briefly discuss the current knowledge of ALK-positive advanced non-small cell lung cancer. Also, we will touch upon new developments on drugs/combination regimens aimed at inhibiting the ALK-TK, in an attempt to delineate how treatment of ALK-positive disease may change in the next future.

Clinical challenges in targeting anaplastic lymphoma kinase in advanced non-small cell lung cancer

The revolution in individualized therapy for patients with advanced non-small cell lung cancer (NSCLC) has seen the emergence of a number of molecularly targeted therapies for distinct patient molecular subgroups. Activating anaplastic lymphoma kinase (ALK)-gene rearrangement has been detected in 3-7 % of NSCLC cases, and the ALK inhibitor crizotinib is now an approved treatment for patients with tumors harboring this event. However, resistance to ALK-targeted therapies is a ubiquitous problem in the management of advanced ALK-positive NSCLC and can be mediated by secondary kinase mutations or the activation of compensatory alternative oncogenic drivers. New, more potent ALK inhibitors such as ceritinib (LDK378), alectinib (CH5424802), and AP26113 are now emerging, together with an increased knowledge of the molecular basis of resistance. There is a need to evaluate the optimal clinical application of these new agents, either as sequential therapies or in combination with other targeted agents, to combat resistance and prolong survival in patients with ALK-positive NSCLC. The remarkable clinical activity of ALK inhibitors also emphasizes the importance of optimal diagnostic testing algorithms, to ensure that all eligible patients receive these breakthrough therapies.

Prospective screening for ALK: clinical features and outcome according to ALK status

The aim of this study was to analyse the clinico-pathological characteristics and outcomes of a cohort of French patients who were prospectively screened for Anaplastic Lymphoma Kinase (ALK) rearrangement. One hundred and sixteen consecutive patients screened for ALK rearrangement to be recruited into a crizotinib registration trial were included from eight French centres. ALK rearrangement was detected by fluorescence in situ hybridization. Seventeen patients (14.6%) were positive for ALK. ALK+ patients were younger (p = 0.049) and more likely to be males (p=0.032), non- or light-smokers (p = 0.048) and without underlying respiratory disease (p=0.025) compared to ALK- patients. Thyroid-transcription factor-1 expression was present in all ALK+ tumours. ALK+ tumours tended to have lymph node and brain metastases. In multivariate analyses, gender, smoking history and N stage were independently associated with ALK status. Median overall survival (OS) was not reached for ALK+ patients and was significantly longer than for ALK- patients (hazard ratio for death for ALK- patients 2.98; 95% CI [1.29-6.90], p=0.01). French ALK+ patients present a specific phenotype. ALK rearrangement should be determined to improve OS with an effective targeted therapy.

Testing for anaplastic lymphoma kinase rearrangement to target crizotinib therapy: oncology, pathology and health economic perspectives

Crizotinib is a first-in-class oral anaplastic lymphoma kinase (ALK) inhibitor targeting ALK-rearranged non-small-cell lung cancer. The therapy was approved by the US FDA in August 2011 and received conditional marketing approval by the European Commission in October 2012 for advanced non-small-cell lung cancer. A break-apart FISH-based assay was jointly approved with crizotinib by the FDA. This assay and an immunohistochemistry assay that uses a D5F3 rabbit monoclonal primary antibody were also approved for marketing in Europe in October 2012. While ALK rearrangement has relatively low prevalence, a clinical benefit is exhibited in more than 85% of patients with median progression-free survival of 8-10 months. In this article, the authors summarize the therapy and alternative test strategies for identifying patients who are likely to respond to therapy, including key issues for effective and efficient testing. The key economic considerations regarding the joint companion diagnostic and therapy are also presented. Given the observed clinical benefit and relatively high cost of crizotinib therapy, companion diagnostics should be evaluated relative to response to therapy versus correlation alone whenever possible, and both high inter-rater reliability and external quality assessment programs are warranted.

Targeting ALK in patients with advanced non small cell lung cancer: biology, diagnostic and therapeutic options

The discovery of EML4-ALK fusion gene in a subgroup of patients with lung adenocarcinoma led to the development of a new class of agents, the ALK inhibitors, and dramatically improved the clinical outcome of these patients. The striking results from clinical trials with crizotinib, the first ALK inhibitor evaluated, allowed the accelerated approval of crizotinib from the USA Food and Drug Administration (FDA). Despite the high initial results, patients acquire resistance to crizotinib, and different next generation ALK kinase inhibitors have been developed. In the current review, we will analyze the biology of EML4-ALK gene, the acquired resistance mechanisms to crizotinib, the therapeutic strategies, currently under evaluation, designed to overcome crizotinib resistance, and the open issues that need to be addressed in order to improve outcome in ALK+ Non Small Cell Lung Cancer (NSCLC) patients.

ALK inhibitors in the treatment of advanced NSCLC

Pharmacologic agents that target protein products of oncogenes in tumors are playing an increasing clinical role in the treatment of cancer. Currently, the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) represent the standard of care for patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring activating EGFR mutations. Subsequently other genetic abnormalities with "driver" characteristics - implying transforming and tumor maintenance capabilities have been extensively reported in several small distinct subsets of NSCLC. Among these rare genetic changes, anaplastic lymphoma kinase (ALK) gene rearrangements, most often consisting in a chromosome 2 inversion leading to a fusion with the echinoderm microtubule-associated protein like 4 (EML4) gene, results in the abnormal expression and activation of this tyrosine kinase in the cytoplasm of cancer cells. This rearrangement occurs in 2-5% of NSCLC, predominantly in young (50 years or younger), never- or former-smokers with adenocarcinoma. This aberration most commonly occurs a independently of EGFR and KRAS gene mutations. A fluorescent in situ hybridization assay was approved by the US Food and Drug Administration (FDA) as the standard method for the detection of ALK gene rearrangement in clinical practice and is considered the gold standard. Crizotinib, a first-in-class dual ALK and c-MET inhibitor, has been shown to be particularly effective against ALK positive NSCLC, showing dramatic and prolonged responses with low toxicity, predominantly restricted to the gastro-intestinal and visual systems, and generally self-limiting or easily managed. However, resistance to crizotinib inevitably emerges. The molecular mechanisms of resistance are currently under investigation, as are therapeutic approaches including crizotinib-based combination therapy and novel agents such as Hsp90 inhibitors. This review aims to present the current knowledge on this fusion gene, the clinic-pathological profile of ALK rearranged NSCLC, and to review the existing literature on ALK inhibitors, focusing on their role in the treatment of NSCLC.

Mechanisms of resistance to EGFR tyrosine kinase inhibitors gefitinib/erlotinib and to ALK inhibitor crizotinib

The discovery of several molecular alterations that underlie non-small cell lung cancer (NSCLC) pathogenesis has led to the development of targeted therapies. In particular, gefitinib and erlotinib have become the standard of care in patients harboring epidermal growth factor receptor mutations, while crizotinib showed an impressive efficacy in patients with ALK-positive NSCLC. Nevertheless, the occurrence of clinical resistance limits the long term results of these novel agents. The identification of the molecular mechanisms responsible for acquired resistance to targeted therapy is crucial in order to pursue the creation of rational strategies to overcome resistance. In the current review, we will focus on the acquired resistance mechanisms to EGFR-TKIs and crizotinib and the therapeutic strategies currently under study to overcome resistance.

Crizotinib versus chemotherapy in advanced ALK-positive lung cancer

BACKGROUND

In single-group studies, chromosomal rearrangements of the anaplastic lymphoma kinase gene (ALK) have been associated with marked clinical responses to crizotinib, an oral tyrosine kinase inhibitor targeting ALK. Whether crizotinib is superior to standard chemotherapy with respect to efficacy is unknown.

METHODS

We conducted a phase 3, open-label trial comparing crizotinib with chemotherapy in 347 patients with locally advanced or metastatic ALK-positive lung cancer who had received one prior platinum-based regimen. Patients were randomly assigned to receive oral treatment with crizotinib (250 mg) twice daily or intravenous chemotherapy with either pemetrexed (500 mg per square meter of body-surface area) or docetaxel (75 mg per square meter) every 3 weeks. Patients in the chemotherapy group who had disease progression were permitted to cross over to crizotinib as part of a separate study. The primary end point was progression-free survival.

RESULTS

The median progression-free survival was 7.7 months in the crizotinib group and 3.0 months in the chemotherapy group (hazard ratio for progression or death with crizotinib, 0.49; 95% confidence interval [CI], 0.37 to 0.64; P<0.001). The response rates were 65% (95% CI, 58 to 72) with crizotinib, as compared with 20% (95% CI, 14 to 26) with chemotherapy (P<0.001). An interim analysis of overall survival showed no significant improvement with crizotinib as compared with chemotherapy (hazard ratio for death in the crizotinib group, 1.02; 95% CI, 0.68 to 1.54; P=0.54). Common adverse events associated with crizotinib were visual disorder, gastrointestinal side effects, and elevated liver aminotransferase levels, whereas common adverse events with chemotherapy were fatigue, alopecia, and dyspnea. Patients reported greater reductions in symptoms of lung cancer and greater improvement in global quality of life with crizotinib than with chemotherapy.

CONCLUSIONS

Crizotinib is superior to standard chemotherapy in patients with previously treated, advanced non-small-cell lung cancer with ALK rearrangement. (Funded by Pfizer; ClinicalTrials.gov number, NCT00932893.).

[Crizotinib: a targeted therapy in advanced ALK-positive non-small cell lung cancer]

Crizotinib is a small orally-administered ALK inhibitor for patients with non-small cell lung cancer with EML4-ALK rearrangement (echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase). This fusion gene is detected with a break apart fluorescence in situ hybridization (FISH) assay. Phase I to III trials have shown an interesting disease control rate and acceptable tolerability. Crizotinib is available in France under temporary use authorization. New potentially effective therapeutics in ALK-positive NSCLC are being developed.

Identification of driver mutations in lung cancer: first step in personalized cancer

Non-small cell lung cancer (NSCLC) has recently been associated with interesting molecular characteristics that have important implications in carcinogenesis and response to targeted therapies. Targeted therapies, if given to a patient subpopulation enriched by the presence of relevant molecular targets, can often abrogate cell signaling that perpetuates cancer progression. For instance, several molecular alterations have been defined as "driver mutations," such as mutations in EGFR and EML4-ALK fusion gene. Other key signaling pathways have also been identified as novel targets for lung cancer treatment. These first steps towards personalized medicine represent a shift in the management of NSCLC. Indeed, NSCLC should no longer be viewed as one common generic tumor but rather as a collection of more rare diseases with different biological behaviors and different sensitivities to targeted treatments. We are now clearly entering an era of personalized medicine for NSCLC cancers, and the development of molecular profiling technologies to assess DNA provides the potential to tailored medical care.

Molecular pathology of non-small cell lung cancer: a practical guide

The traditional distinction between small cell lung cancer and non-small cell lung cancer (NSCLC) is no longer sufficient for treatment planning. It is advised to handle small diagnostic specimens prudently because they are often the only specimen available for molecular analysis. Pathologists are experiencing pressure to subclassify lung carcinoma based on extremely small tumor samples, because NSCLC tumor subtyping is now essential to determine molecular testing strategies. Evaluation for EGFR mutations and ALK rearrangements are now considered to be the standard of care in advanced-stage pulmonary adenocarcinomas. Immunohistochemical stains can aid in subclassifying NSCLC, but performing these ancillary studies can significantly reduce the quantity of tissue available for molecular tests, requiring careful balancing of these 2 needs. The pathologist plays a pivotal role in facilitating clear and timely communication between the clinical oncology care team and the molecular laboratory to ensure that the appropriate tests are ordered and optimal material is submitted for testing.