Abnormalities of epidermal growth factor receptor in lung squamous-cell carcinomas, adenosquamous carcinomas, and large-cell carcinomas: tyrosine kinase domain mutations are not rare in tumors with an adenocarcinoma component

Current management of uncommon EGFR mutations in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations are frequently implicated in non-small cell lung cancer (NSCLC). Though these typically involve exon 19 in-frame deletions or L858R mutations in exon 21, uncommon EGFR mutations comprise 10-15 % of all EGFR mutations. These most frequently include G719X mutations in exon 18, L861Q mutations in exon 21, S768I mutations in exon 20, and in-frame insertions and/or duplications in exon 20. It is crucial to understand these distinct variants and their specific responses to active treatment options to optimize care. In this review, we discuss these uncommon mutations in depth and dissect the current literature regarding their treatment outcomes and subsequent evidence-based management guidelines.

Novel targeted therapies for advanced non-small lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer accounting for almost 80%-85% of all lung cancer cases. Unfortunately, more than half of the patients will be diagnosed with advanced disease at the time of presentation, which makes their disease incurable. Historically, the 5 year overall survival for advanced NSCLC was 5%. However, there has been a significant increase in our understanding of the genetic basis of NSCLC, which has led to development of both immunotherapy and targeted therapy agents. This has improved the 5 year overall survival to become within the range of 15%-50% depending on certain mutations and biomarkers. Over the last decade the United States Food and Drug Administration (FDA) has approved almost 20 new targeted therapies and clinical trials are still undergoing to evaluate more novel agents. In this review, we will present recent updates on novel targeted therapies.

How should molecular findings be integrated in the classification for lung cancer?

The use of molecular diagnostics in the diagnosis and management of patients with advanced lung cancer has become widespread. Although molecular classification has increasingly been incorporated in the pathologic classification of certain types of human tumors (particularly within the hematologic, glial, and bone/soft tissue malignancies), genetic findings have not been formally incorporated into the pathologic classification of lung cancer, which presently relies solely on the assessment of histologic and immunophenotypic characteristics. Whether molecular classification should be adopted in lung cancer would depend on the diagnostic, prognostic, and predictive impacts of such classification-and whether these impacts confer significant values additive to those derived from the routine histologic and immunophenotypic assessment. We provide a brief overview on the genetics of lung cancer, including adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors (small cell carcinoma, large cell neuroendocrine carcinoma, and carcinoid tumors). We consider the values of molecular information with some examples, in terms of the current diagnostic, prognostic, and predictive impacts. Finally, we discuss the conceptual and technical challenges of adopting a molecular classification for lung cancer in clinical management for patients. While there are conceptual and technical hurdles to tackle in implementing molecular classification in the pathologic classification of lung cancer, such integrated histologic-molecular diagnosis may allow one to personalize and optimize therapy for patients with advanced lung cancer.

Treatment for Patients With Early Stage Adenosquamous Lung Cancer

Introduction

Adenosquamous lung cancer (ASC) is a rare type of NSCLC with poor prognosis. There is no consensus on the necessity of adjuvant chemotherapy and the selection of surgical procedures for patients with early stage lung cancer. Few studies have investigated the treatment for early stage ASC.

Methods

All cases of TNM stage I ASC as per the seventh edition of the American Joint Committee on Cancer staging system were identified from the Surveillance, Epidemiology, and End Results database from 2004 to 2016. The prognostic factors of the primary cohort were identified. Clinical characteristics, first-line treatments, surgical procedures, and survival data, including overall survival and cancer-specific survival, were analyzed.

Results

A total of 1251 patients were included. The mean age of the patients was 70 years (±9.5 y). Male and white patients accounted for larger proportions. There were 656 and 595 patients with stages IA and IB, respectively. The mean tumor size was 26.2 mm (±10.7 mm). With respect to the treatment, 139 patients who received only chemotherapy had the worst prognosis. Similar outcomes were observed in both the surgery and adjuvant therapy groups. Nevertheless, adjuvant chemotherapy could improve survival outcomes of patients with a tumor size of 4 to 5 cm. Of the 1075 patients who underwent surgery, there were 224 cases of sublobar resection, 834 cases of lobectomy, and 17 cases of extended or sleeve lobectomy. The results revealed that patients who underwent lobectomy had better prognosis.

Conclusions

Early stage ASC has a poor prognosis. Adjuvant chemotherapy was found to have no considerable benefit in patients with stage I disease (eighth edition). Lobectomy or other radical surgeries are recommended as they can improve overall survival of patients with ASC.

Tumor-educated platelet as liquid biopsy in lung cancer patients

Lung cancer is the most frequent cancer for males and third most frequent cancer for females. Targeted therapy drugs based on molecular alterations, such as angiogenesis inhibitors, epidermal growth factor receptor (EGFR) inhibitors, and anaplastic lymphoma kinase (ALK) inhibitors are important part of treatment of NSCLC. However, the quality of the available tumor biopsy and/or cytology material is sometimes not adequate to perform the necessary molecular testing, which has prompted the search for alternatives. This review examines the use of tumor-educated platelet (TEP) as a liquid biopsy in lung cancer patients. The development of sensitive and accurate techniques have made it possible to detect the specific genetic alterations for which targeted therapies are already available. Liquid biopsy offers opportunities to detect resistance mechanisms at an early stage. To conclude, tumor-educated platelet has the potential to be used as liquid biopsy for a variety of clinical and investigational applications.

Simultaneous Detection of the T790M and L858R Mutations in the EGFR Gene by Oligoribonucleotide Interference-PCR

A de novo single-nucleotide mutation in the EGFR gene can cause the development of lung cancer. EGFR tyrosine kinase inhibitors (EGFR-TKIs) are used for clinical treatment of such lung cancers, but acquired resistance often mitigates their efficacy. Accordingly, monitoring of de novo and acquired nucleotide mutations is essential for clinical treatment of lung cancers with EGFR-TKIs. Previously, we reported that oligoribonucleotide interference-PCR (ORNi-PCR) can accurately and cost-effectively detect single-nucleotide mutations. In this study, we applied ORNi-PCR to simultaneous detection of the de novo L858R and acquired T790M mutations in the EGFR gene in lung cancer cells. First, we established optimal experimental conditions for ORNi-PCR to simultaneously detect the two single-nucleotide mutations in genomic DNA from lung cancer cells. The conditions we established could also be used for ORNi-PCR using complementary DNA reverse-transcribed from extracted RNA. We found that ORNi-PCR could detect lung cancer cells possessing both single-nucleotide mutations among a large number of cells harboring wild-type sequences, even when the cancer cells constituted less than ~0.2% of all cells. Our findings demonstrate that ORNi-PCR can simultaneously detect multiple single-nucleotide mutations in a gene of interest and might therefore be useful for simultaneous detection of EGFR mutations in clinical examinations.

Diagnostic and Predictive Immunohistochemistry for Non-Small Cell Lung Carcinomas

Non-small cell lung carcinoma (NSCLC) accounts for significant morbidity and mortality worldwide, with most patients diagnosed at advanced stages and managed increasingly with targeted therapies and immunotherapy. In this review, we discuss diagnostic and predictive immunohistochemical markers in NSCLC, one of the most common tumors encountered in surgical pathology. We highlight 2 emerging diagnostic markers: nuclear protein in testis (NUT) for NUT carcinoma; SMARCA4 for SMARCA4-deficient thoracic tumors. Given their highly aggressive behavior, proper recognition facilitates optimal management. For patients with advanced NSCLCs, we discuss the utility and limitations of immunohistochemistry (IHC) for the "must-test" predictive biomarkers: anaplastic lymphoma kinase, ROS1, programmed cell death protein 1, and epidermal growth factor receptor. IHC using mutant-specific BRAF V600E, RET, pan-TRK, and LKB1 antibodies can be orthogonal tools for screening or confirmation of molecular events. ERBB2 and MET alterations include both activating mutations and gene amplifications, detection of which relies on molecular methods with a minimal role for IHC in NSCLC. IHC sits at the intersection of an integrated surgical pathology and molecular diagnostic practice, serves as a powerful functional surrogate for molecular testing, and is an indispensable tool of precision medicine in the care of lung cancer patients.

Research progress of the clinicopathologic features of lung adenosquamous carcinoma

Adenosquamous carcinoma (ASC) of the lung, a biphasic malignant tumor arising from lung tissue, is a special subtype of non-small-cell lung cancer (NSCLC) with low incidence but high tendency of invasion and poor prognosis. ASC contains components of lung adenocarcinoma (AC) and lung squamous cell carcinoma (SCC). However, there is a remarkable difference between ASC and other NSCLCs in clinical features, suggesting that ASC is not a simple mixture of AC and SCC, but is rather a more complex carcinoma with a unique molecular phenotype. At present, the research on ASC is still rare, mostly because of its complicated molecular mechanism and unclear pathological origin. The lack of cognition of ASC limits its early diagnosis and treatment, and a set of mature and effective treatment programs has not been proposed yet. In-depth study of the molecular characteristics and clinical features of ASC will not only help to better understand the scientific issues, including phenotype switching of lung cancer, the origin of tumor development, and tumor heterogeneity, but also contribute to the development of its individualized treatment. This review summarizes the recent studies concerning the clinicopathologic features and the molecular mechanisms of ASC to further facilitate the development of its individualized treatment.

Efficacy of icotinib in advanced lung squamous cell carcinoma

BACKGROUND

There are controversial data supporting the efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in patients with advanced lung squamous cell carcinoma (SCC). In this study, the efficacy of icotinib in unselected and EGFR-mutated patients with lung SCC was assessed.

METHODS

We retrospectively analyzed the survival time of unselected advanced lung SCC patients treated with icotinib for at least 5 months between June 2013 and June 2016, and selected appropriate EGFR-mutated advanced lung ADC patients to have 1:1 ratio of propensity score matching with EGFR-mutated advanced lung SCC patients, and matching factors were age, sex, clinical stage, Karnofsky performance status (KPS), smoking history, EGFR mutation type, and treatment lines.

RESULTS

A total of 487 unselected advanced lung SCC patients were available for analysis of icotinib treatment efficacy. The progression-free survival (PFS) was 13.0 months (95% CI 12.2-13.8), the overall survival (OS) was 16.0 months (95% CI 14.7-17.3), and the objective response rate (ORR) was 41.3%. After propensity score matching, 78 EGFR-mutated lung SCC and 78 EGFR-mutated lung ADC patients were selected and compared. Although no statistical difference was found, ADC patients were associated with a longer PFS (15.8 months vs 12.7 months, P = 0.275) and OS (24.2 months vs 18.5 months, P = 0.150), and a better ORR (59.0% vs 48.7%, P = 0.199) than compared with SCC patients when treated with icotinib.

CONCLUSION

Icotinib has a modest therapeutic effect in patients with advanced lung SCC, especially for the population with EGFR mutations.

Expression of phosphatase and tensin homolog and programmed cell death ligand 1 in adenosquamous carcinoma of the lung

BACKGROUND

Lung adenosquamous carcinoma (ASC) is a rare variant of non-small cell lung cancer (NSCLC) with poor prognosis. Certain biological differences may exist between these tumors and other common histological types of NSCLC, including adenocarcinoma (ADC) and squamous cell carcinoma (SCC). The phosphoinositide 3-kinase (PI3K) pathway, which links oncogenes and multiple receptor classes to essential cellular functions, is activated by phosphatase and tensin homolog (PTEN) loss. The PTEN loss has been suggested to induce programmed cell death ligand 1 (PD-L1) expression in various cancer types.

OBJECTIVE

Here, we sought to determine the relationships between the expression of PTEN and PD-L1 in each component of ASC with ADC and SCC, and clinical parameters.

MATERIAL AND METHODS

Tissue microarrays of 148 cases of surgically resected lung ADC and 102 cases of SCC, as well as full sections from 28 ASC cases, were analyzed immunohistochemically for the expression of PTEN and PD-L1.

RESULTS

PD-L1 expression was similar between the adenocarcinoma component of ASC vs. lung ADC and between the squamous component of ASC vs. lung SCC. PTEN loss was higher in lung ADC than in the adenocarcinoma component of ASC and significantly higher in lung SCC than in the squamous component of ASC. PD-L1 expression was higher in the squamous component than in the glandular component of the 28 ASC cases, but PTEN loss was similar. Overall, PTEN loss was higher in lung SCC than in lung ADC and both components of ASC. In lung SCC and glandular portions of ASC, PD-L1 expression levels were significantly associated with those of PTEN. The loss of PTEN correlated with smoking status in patients with lung ADC.

CONCLUSIONS

Our results implied that both squamous and glandular components of ASC may share the same oncogenic driver pathway for carcinogenesis. However, the squamous cell components of ASC likely escape the immune surveillance better than the glandular components due to higher PD-L1 expression.

Clinical and genetic features of lung squamous cell cancer in never-smokers

To evaluate the importance of specific driver mutations to the development and outcome of lung squamous cell cancer (SQCC) in never-smokers, we assessed the clinicopathological characteristics and outcomes of 597 patients who underwent complete resection of SQCCs. In total, 88 (14.7%) never-smokers and 509 (85.3%) ever-smokers were compared. The never-smokers included more females (42.05% vs. 1.57%, P < 0.001) and more often had a personal history of malignant disease (9.09% vs. 2.36%, P = 0.003). The tumors of never-smokers were more often poorly differentiated (70.45% vs. 53.24%, P = 0.010) and more often contained oncogenic mutations (21.05% vs 11.05%, P = 0.023), particularly EGFR mutations (13.16% vs 3.40%, P = 0.001). Never-smokers also tended to have poorer OS than smokers. Our results suggest lung SQCCs in never-smokers are a subtype distinct from SQCCs occurring in smokers.

Efficacy of icotinib in lung squamous-cell cancer: A real-world experience from single institution

AIM

Squamous cell carcinoma is a less common type of nonsmall cell lung cancer (NSCLC) which associates with a poor clinical prognosis and lacks specific therapy. This study aimed to evaluate the efficacy and safety of icotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has proven to be effective in EGFR-mutated NSCLC, in patients with lung squamous-cell cancer.

METHODS

Retrospective analysis was conducted in patients who had advanced lung squamous-cell cancer confirmed by cytology or histology. Patients were treated orally with icotinib (125 mg, three times daily) until event of unacceptable toxicity, disease progression or death. The primary endpoint was overall survival. The secondary endpoints were progression-free survival, overall response rate and disease control rate.

RESULTS

Between January 2014 and May 2016, 20 patients were enrolled and evaluated for the efficacy and safety of icotinib. Overall, the median overall survival and progression-free survival were 9.93 months (95% confidence interval (CI): 3.46-16.40) and 3.0 months (95% CI: 0.00-8.35), respectively. The overall response rate and disease control rate were 20% and 70%, respectively. For treatment-naive patients (n = 11), the overall survival and progression-free survival were 9.93 months (95% CI: 0.00-23.49) and 6.27 months (95% CI: 0.00-12.61); the response rate and disease control rate were 27.3% and 54.5%, respectively. The overall survival and progression-free survival of patients treated with second- or multiple-line icotinib treatment (n = 9) were 6.5 months (95% CI: 0.80-12.20) and 1.2 months (95% CI: 1.10-1.30). A total of 11 patients experienced at least one treatment-related adverse event, most of which were mild to moderate. The most common manifestations were rash (n = 6, 30%) followed by diarrhea (n = 2, 10%).

CONCLUSION

Icotinib has demonstrated a favorable efficacy and safety profile in patients with advanced lung squamous-cell cancer.

Efficacy of EGFR tyrosine kinase inhibitors for non-adenocarcinoma lung cancer patients harboring EGFR-sensitizing mutations in China

PURPOSE

EGFR tyrosine kinase inhibitors (TKIs) have been established as standard therapy for EGFR-mutated adenocarcinomas; for non-adenocarcinoma non-small cell lung cancer (NSCLC) patients, this therapy remains debatable.

METHODS

Stage IIIB/IV patients with non-adenocarcinoma NSCLC who underwent EGFR testing were identified at the Shanghai Chest Hospital from January 2009 to September 2014.

RESULTS

A total of 51 patients with EGFR-sensitizing mutations [26 patients with squamous cell carcinoma (SCC), 15 patients with adenosquamous cell carcinoma (ASC), and 10 patients with large cell lung carcinoma (LCLC)] were available for analysis of EGFR TKI treatment efficacy. The progression-free survival (PFS) for the 51 patients harboring EGFR-sensitizing mutations was 4.93 months (95 % CI 3.93-5.93). The PFS for the SCC, ASC, and LCLC patients was 3.98 months (95 % CI 3.32-4.63), 8.08 months (95 % CI 4.17-12.00), and 4.40 months (95 % CI 1.56-7.24), respectively. Among the 51 non-adenocarcinoma NSCLC patients, the PFS of the non-smokers and smokers was 5.49 months (95 % CI 3.28-7.70) and 3.78 months (95 % CI 2.61-4.95), respectively (P = 0.036). The PFS for the patients with a deletion in exon 19 and for those with an exon 21 L858R mutation was 5.16 months (95 % CI 4.21-6.11) and 4.04 months (95 % CI 2.35-5.73), respectively (P = 0.414).

CONCLUSIONS

EGFR TKIs could be an option for the treatment of EGFR-mutated non-adenocarcinoma NSCLC, especially for patients with adenosquamous histology and non-smokers.

Lung Cancer Genomics in the Era of Accelerated Targeted Drug Development

Lung cancer is the leading cause of cancer-related deaths in the United States and the 5-year overall survival outlook for a patient has not improved in several decades. Recently, however, molecular and genomic profiling of the lung tumors has revealed recurring somatic mutations. As a result the therapeutic landscape of lung cancer is undergoing a paradigm shift from a purely histology-based understanding of the disease to subtype distinctions based on tumor genetics, which has launched cancer-specific, mechanism-based targeted therapies with clear benefit to patients. While targeted therapy advancements are being made at an ever increasing rate, a new challenge in the form of drug resistance has also emerged. This review summarizes the current literature for these issues.

Epidermal growth factor receptor tyrosine kinase inhibitors with conventional chemotherapy for the treatment of non-small cell lung cancer

We report a Chinese male patient with advanced stage lung squamous cell carcinoma who developed brain metastases after responding to treatment comprising six cycles of conventional chemotherapy with docetaxel and cisplatin. The patient was then treated with oral erlotinib (150 mg/day) and whole-brain radiation therapy followed by four cycles of docetaxel and carboplatin chemotherapy. The patient then received gefitinib (250 mg/day) as a maintenance therapy until the end of the follow-up period. In this patient, progression-free survival, defined as the interval from the initiation of first-line chemotherapy to the cessation of erlotinib due to progressive disease or death from any cause, was 3 months. Overall survival, defined as the interval from the initiation of first-line chemotherapy to death from any cause, was 75 months. Erlotinib was well tolerated in combination with whole-brain radiation therapy and a favorable objective response rate was observed. Furthermore, targeted drug treatment warrants consideration in patients with a negative epidermal growth factor receptor mutation status and male patients with a history of smoking.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Advanced Squamous Cell Lung Cancer

BACKGROUND

The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in squamous cell carcinoma (SCC) of the lung remains controversial, and the role of EGFR testing in patients with SCC of the lung remains debatable.

PATIENTS AND METHODS

We retrospectively identified patients with stage IIIB or IV SCC of the lung who had undergone EGFR testing at Shanghai Chest Hospital from January 2009 to December 2013.

RESULTS

A total of 29 EGFR mutation-positive patients (22 patients had received TKI therapy and 7 had not) and 151 EGFR wild-type patients (27 patients had received TKI therapy and 124 had not) were available for an analysis of efficacy. The EGFR mutation-positive patients had significantly improved overall survival (OS) with EGFR TKI therapy compared with those who had not received EGFR TKIs (18.04 months [95% confidence interval (CI), 13.47-22.61 months] vs 13.18 months [95% CI, 5.22-21.13]; P = .015). Patients with wild-type EGFR did not have an improvement in OS with TKI therapy compared with those who had not received TKIs (14.03 months [95% CI, 11.11-16.9 months] vs. 13.63 months [95% CI, 11.91-15.36]; P = .927). The progression-free survival (PFS) for EGFR mutation-positive and EGFR wild-type patients was 3.94 months (95% CI, 2.73-5.15 months) and 1.94 months (95% CI, 0.89-2.99 months), respectively (P = .004).

CONCLUSION

EGFR TKIs could be an option for the treatment of SCC, and EGFR mutation detection can help to select a subgroup of patients who would have the best response to TKIs.

Pharmacogenomics and targeted therapy of cancer: Focusing on non-small cell lung cancer

Recent studies have been established high degree of genetic diversity in solid organ tumors among individuals and even between individual tumor cells. This intratumor and intertumor genetic diversity results in a heterogeneous tumor with unique characteristics which potentially allows effective drug therapy. The goal of pharmacogenomics is to elucidate the genetic network(s) that underlie drug efficacy and drug resistance. Advances in targeted and personalized therapy play an increasingly important role in many common cancers, notably lung cancer, due to the high incidence, prevalence, mortality and the greater tendency towards drug resistance seen in these patients. Non-small cell lung cancer (NSCLC) is characterized by mutations in the epidermal growth factor receptor (EGFR) and or downstream kinase pathways. This has led to the development of highly selective monoclonal antibodies and EGFR tyrosine kinase inhibitors (EGFR-TKIs) to prevent cancer initiation, proliferation, differentiation, angiogenesis, survival, and invasion. However, resistance to many of these new treatments is induced and further pharmacogenomic analysis has revealed mutations associated with increased or reduced drug efficacy. Combinations of kinase inhibitors or potentially the targeting of cancer stem cells may further increase the success of pharmacogenomics in treating patients with lung cancer.

Epidermal growth factor receptor variant III mutation in Chinese patients with squamous cell cancer of the lung

Background

The aim of this study was to investigate the distribution of epidermal growth factor receptor (EGFR)vIII mutation in Chinese non-small cell lung cancer (NSCLC) patients and to explore the likely relationship between EGFRvIII mutation and response to EGFR-tyrosine kinase inhibitors (TKIs) in squamous cell carcinoma (SCC).

Methods

Samples were derived from two patient cohorts: (i) 114 early-stage NSCLC who received surgical resection; and (ii) 31 advanced-stage SCC who received EGFR-TKI EGFRvIII. EGFR and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations were detected by reverse transcription polymerase chain reaction (RT-PCR), denaturing high-performance liquid chromatography, and PCR-restriction fragment length polymorphism, respectively. The associations of EGFRvIII, EGFR, and KRAS mutations with clinical outcome of EGFR-TKI treatment were evaluated using the Kaplan-Meier method, descriptive analysis, and multi-variable Cox regression analysis.

Results

In the first cohort, EGFRvIII mutation was detected in eight of 114 (7.0%) patients, including 11.1% (6/54) SCC and 3.6% (2/55) adenocarcinomas (ADC) (P = 0.269). In the second cohort, five (16.1%) and 10 out of 31 advanced SCC presented EGFRvIII and EGFR mutations, respectively. No appreciable discrepancy of progression-free survival or disease control rate was detected between the patients with and without EGFRvIII mutation (P > 0.05). However, longer median overall survival (OS) was observed in patients harboring EGFRvIII compared to those without EGFRvIII, although the difference did not reach statistical significance.

Conclusion

The frequency of EGFRvIII mutation in SCC was higher than in ADC. SCC patients harboring EGFRvIII mutations had a tendency for prolonged OS.

Relationship of thyroid transcription factor 1 to EGFR status in non-small-cell lung cancer

BACKGROUND

Activating mutations of the epidermal growth factor receptor (EGFR) gene are known to drive a proportion of non-small-cell lung cancers. Identification of lung cancers harbouring such mutations can lead to effective treatment using one of the agents that targets and blocks egfr-mediated signalling.

METHODS

All specimens received at the BC Cancer Agency (Vancouver) for EGFR testing were prospectively identified and catalogued, together with clinical information and EGFR status, over a 14-month period.

RESULTS

Specimens from 586 patients were received for EGFR testing, and EGFR status was reported for 509 patients. No relationship between specimen type or site of origin and EGFR test failure rate was identified. Concurrent immunohistochemical (ihc) status for thyroid transcription factor 1 (ttf1) was available for 309 patients. The negative predictive value of ttf1-negative status by ihc was 94.2% for predicting negative EGFR status.

CONCLUSIONS

In patients with limited tissue available for testing, a surrogate for EGFR status would aid in timely management. Immunohistochemistry for ttf1 is readily available and correlates highly with EGFR status. In conjunction with genetic assays, ttf1 could be used to optimize an EGFR testing strategy.

Head and neck squamous cell carcinomas do not express EGFRvIII

PURPOSE

To assess the prevalence of EGFRvIII, a specific variant of EGFR (epidermal growth factor receptor), in 3 well-defined cohorts of head and neck squamous cell carcinoma (HNSCC).

METHODS AND MATERIALS

Immunohistochemistry for the specific detection of EGFRvIII using the L8A4 antibody was optimized on formalin-fixed, paraffin-embedded tissue using glioblastoma tissue. It was compared with EGFR and EGFRvIII RNA expression using a specific reverse transcription-polymerase chain reaction also optimized for formalin-fixed, paraffin-embedded tissue. Tissue microarrays including 531 HNSCCs of various stages with complete clinicopathologic and follow-up data were tested for the presence of EGFRvIII.

RESULTS

None of the 531 cases showed EGFRvIII protein expression. Using an immunohistochemistry protocol reported by others revealed cytoplasmic staining in 8% of cases. Reverse transcription-polymerase chain reaction for the EGFRvIII transcript of the 28 highest cytoplasmic staining cases, as well as 69 negative cases, did not show expression in any of the tested cases, suggesting aspecific staining by a nonoptimal protocol.

CONCLUSIONS

The EGFRvIII mutation is not present in HNSCC. Therefore, EGFRvIII does not influence treatment response in HNSCC and is not a usable clinical prognostic marker.

Molecular biology of lung cancer

Lung cancers are characterised by abundant genetic diversity with relatively few recurrent mutations occurring at high frequency. However, the genetic alterations often affect a common group of oncogenic signalling pathways. There have been vast improvements in our understanding of the molecular biology that underpins lung cancer in recent years and this has led to a revolution in the diagnosis and treatment of lung adenocarcinomas (ADC) based on the genotype of an individual's tumour. New technologies are identifying key and potentially targetable genetic aberrations not only in adenocarcinoma but also in squamous cell carcinoma (SCC) of the lung. Lung cancer mutations have been identified in v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), epidermal growth factor receptor (EGFR), BRAF and the parallel phosphatidylinositol 3-kinase (PI3K) pathway oncogenes and more recently in MEK and HER2 while structural rearrangements in ALK, ROS1 and possibly rearranged during transfection (RET) provide new therapeutic targets. Amplification is another mechanism of activation of oncogenes such as MET in adenocarcinoma, fibroblastgrowth factor receptor 1 (FGFR1) and discoidin domain receptor 2 (DDR2) in SCC. Intriguingly, many of these genetic alternations are associated with smoking status and with particular racial and gender differences, which may provide insight into the mechanisms of carcinogenesis and role of host factors in lung cancer development and progression. The role of tumour suppressor genes is increasingly recognised with aberrations reported in TP53, PTEN, RB1, LKB11 and p16/CDKN2A. Identification of biologically significant genetic alterations in lung cancer that lead to activation of oncogenes and inactivation of tumour suppressor genes has the potential to provide further therapeutic opportunities. It is hoped that these discoveries may make a major contribution to improving outcome for patients with this poor prognosis disease.

Comprehensive analysis of oncogenic mutations in lung squamous cell carcinoma with minor glandular component

BACKGROUND

The mutations in oncogenic genes, such as EGFR, ALK, BRAF, HER2, DDR2, RET, and AKT1, defined subsets of non-small cell lung cancers (NSCLCs) with potential sensitivity to targeted therapies. At present, the mutational spectrum, prevalence, and clinicopathologic characteristics in squamous cell carcinomas with minor (<10%) glandular component (SQCC-mGCs) are not well established.

METHODS

Three hundred ten surgically resected lung squamous cell carcinoma (SQCC) specimens were collected. The histology of all cases was reevaluated using hematoxylin-eosin and immunohistochemistry staining. EGFR, KRAS, HER2, BRAF, PIK3CA, AKT1, and DDR2 mutations, as well as ALK and RET rearrangements, were examined in 310 SQCCs by directed sequencing.

RESULTS

Ninety-five SQCC-mGCs (30.6%) and 215 pure SQCCs (69.4%) were identified. Of the 95 SQCC-mGCs, 26 (27.4%; 95% CI, 18.7%-37.4%) were found to harbor known oncogenic mutations, including 10 with EGFR, seven with KRAS, three with PIK3CA, one with BRAF, one with HER2, one each with EGFR/PIK3CA and KRAS/PIK3CA double mutations, and two with EML4-ALK fusions. Ten of 215 pure SQCCs (4.7%; 95% CI, 2.3%-8.4%) harbored mutations, including seven with PIK3CA, and each with AKT1, DDR2, and EGFR. No RET rearrangements were detected in SQCCs. SQCC-mGCs had a significantly higher rate of mutations in known oncogenic genes than that in pure SQCCs (27.4% vs 4.7%, P<.001). All KRAS mutations occurred in SQCC-mGCs.

CONCLUSIONS

Our results demonstrated that oncogenic mutations in EGFR, KRAS, BRAF, HER2, and ALK were extremely rare or absent in patients with pure SQCC, whereas SQCC-mGC had a relatively high frequency of EGFR, ALK, or KRAS mutations. Prospective identification of these known oncogenic mutations in SQCC-mGC before the initiation of treatment is an essential step to identify which patient could benefit from targeted therapies.

[Advances of molecular targeted therapy in squamous cell lung cancer]

肺鳞癌（squamous-cell lung cancer, SQCLC）是一种常见的肺癌病理类型，全世界每年约40余万人死于肺鳞癌，发病与吸烟密切相关。然而，研究表明，在肺腺癌中有明显疗效的靶向药物却无法让肺鳞癌患者获益，如人表皮生长因子受体（epidermal growth factor receptor, EGFR）抑制剂、间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）抑制剂等。通过大量基因组学研究表明，纤维母细胞生长因子受体1（fibroblast growth factor receptor 1, FGFR1）基因扩增和盘状结构域受体2（the discoidin domain receptor 2, DDR2）基因突变等都可能成为新的用于治疗肺鳞癌的潜在药物分子靶点。此外，肺鳞癌患者基因组中也存在特异性的基因变异位点，这些改变在肺鳞癌细胞周期调控、氧化应激反应、细胞凋亡和鳞状上皮分化过程中发挥了重要作用，也可能为寻找候选分子靶点提供依据。本综述通过回顾近年来肺鳞癌分子靶向治疗的相关研究，分析靶向治疗在肺鳞癌中的研究进展，使肺鳞癌的个体化靶向治疗成为可能。

Adenosquamous cell lung cancer successfully treated with gefitinib: A case report

Although adenosquamous cell lung cancer (ASCLC) is included in the non-small-cell lung cancers (NSCLCs), the number of currently available studies on the response of this type of cancer to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is limited. This is the case report of a 66-year-old female who was referred to the Mito Medical Center (Mito, Japan) with hemoptysis and the chest computed tomography (CT) scan revealed a large cavitary mass in the lower lobe of the left lung. The patient underwent surgical resection of the lesion and the final pathological diagnosis was ASCLC staged as pT2bN2M0. Notably, an EGFR exon 19 deletion was identified in the adenocarcinomatous as well as the squamous cell carcinomatous components of the tumor. Despite adjuvant chemotherapy, the patient developed small cavitary metastases in the lungs bilaterally. Therefore, treatment with gefitinib was initiated. The chest CT scan revealed substantial regression of the metastatic cavitary tumors in both lungs, with thinning of the walls. The patient remains alive and recurrence-free 19 months following the initiation of gefitinib therapy. This case demonstrated an optimal clinical response to gefitinib treatment for EGFR mutation-positive ASCLC, suggesting that gefitinib is a therapeutic option for such a subset of patients with ASCLC.

Efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors for Chinese patients with squamous cell carcinoma of lung harboring EGFR mutation

OBJECTIVE

Epidermal growth factor receptor (EGFR) mutation mostly occurred in lung adenocarcinoma, rarely in squamous cell carcinoma (SQCC). EGFR mutation rate in SQCC varied in previous reports, and the efficacy of EGFR tyrosine kinase inhibitors (TKIs) in SQCC harboring EGFR mutation has not yet been fully evaluated. The aim of this study was to investigate the efficacy EGFR-TKIs for Chinese patients with SQCC of lung harboring EGFR mutation.

PATIENTS AND METHODS

Two cohorts of patients were analyzed. The first cohort included 146 consecutive post-operation SQCC patients from January 2008 to October 2012. The second cohort included 63 patients with advanced SQCC receiving EGFR-TKIs treatment. EGFR mutation analysis was performed with Real-time PCR method. The pathologic diagnosis was validated with immunohistochemistry (IHC) for patients harboring activated EGFR mutation. And the efficacy of EGFR-TKIs in squamous cell carcinoma of lung (SQCC) was evaluated in patients with activated EGFR mutations.

RESULTS

In the first cohort, 146 resected patients, EGFR mutations were detected in 3 patients, with the mutation rate of 2.0%. In cohort two, 63 patients treated with EGFR-TKIs, 15 patients possessed activated EGFR mutations. The response rate and disease control rate in these patients was 26.7% and 66.7% respectively. 5 patients had disease control over 6 months. The progression free survival (PFS) in EGFR-mutated patients was 3.9 months.

CONCLUSIONS

In Chinese SQCC patients, EGFR mutation rate was extremely low. EGFR-TKIs seemed to be less effective in EGFR-mutated SQCC patients, but some patients could still obtain benefit from EGFR-TKIs. To identify this part of patients, further study was warranted in the future.

Clinical testing for molecular targets for personalized treatment in lung cancer

Lung cancer is the leading cause of cancer mortality worldwide. Over the past decades, the management of advanced stage lung cancer has been revolutionized from very limited options of systemic chemotherapy with limited efficacy to the present stage of testing for biomarkers (epidermal growth factor receptor (EGFR), gene mutations) to guide therapeutic decision and to improve efficacy of treatment. Relevant advancement in understanding of lung cancer biology also revealed that different lung tumours may carry different cancer driver gene mutations and thus adopt different carcinogenic pathways. These cancer driver gene mutations were found to be mutually exclusive in individual lung tumour further supporting the rationale of testing tumour sample for the presence of these mutations, especially when there could be corresponding specific agents against these molecular targets. The aim of this article is to review the current understanding of molecular targets that are important in the personalized therapy of lung cancer and how the testing for these molecular targets, namely EGFR, KRAS and ALK, will guide therapeutic decision in advanced stage lung cancer.

Prognostic impact of serum CYFRA 21-1 in patients with advanced lung adenocarcinoma: a retrospective study

BACKGROUND

Serum CYFRA 21-1 is one of the most important serum markers in the diagnosis of non-small cell lung cancer (NSCLC), especially squamous-cell carcinoma. However, it remains unknown whether pretreatment serum CYFRA 21-1 values (PCV) may also have prognostic implications in patients with advanced lung adenocarcinoma.

METHODS

We retrospectively reviewed the data of 284 patients (pts) who were diagnosed as having advanced lung adenocarcinoma and had received initial therapy.

RESULTS

Of the study subjects, 121 pts (43%) had activating epidermal growth factor receptor (EGFR) mutations (Mt+), while the remaining 163 pts (57%) had wild-type EGFR (Mt-). Univariate analysis identified gender (male/ female), ECOG performance status (PS) (0-1/ ≥2), PCV (<2.2 ng/ml/ ≥2.2 ng/ml), EGFR mutation status (Mt+/ Mt-), pretreatment serum CEA values (<5.0 ng/ml/ ≥5.0 ng/ml), smoking history (yes/ no) and EGFR-TKI treatment (yes/ no) as prognostic factors (p = .008, p < .0001, p < .0001, p < .0001, p = .036, p = .0012, p < .0001 respectively). Cox's multivariate regression analysis identified PCV < 2.2ng/ml as the only factor significantly associated with prolonged survival (p < .0001, hazard ratio: 0.43, 95% CI 0.31-0.59), after adjustments for PS (p < .0001), EGFR mutation status (p = .0069), date of start of initial therapy (p = .07), gender (p = .75), serum CEA level (p = .63), smoking history (p = .39) and EGFR-TKI treatment (p = .20). Furthermore, pts with Mt+ and PCV of <2.2 ng/ml had a more favorable prognosis than those with Mt+ and PCV of ≥2.2 ng/ml (MST: 67.0 vs. 21.0 months, p < .0001), and patients with Mt- and PCV of <2.2 ng/ml had a more favorable prognosis than those with Mt- and PCV of ≥2.2 ng/ml (MST: 24.1 vs. 10.2 months, p < .0001).

CONCLUSION

PCV may be a potential independent prognostic factor in both Mt+ and Mt- patients with advanced lung adenocarcinoma.

Molecular profiling in non-small cell lung cancer: a step toward personalized medicine

CONTEXT

Lung carcinoma is the result of sequential accumulation of genetic and epigenetic changes. Lung adenocarcinoma is a heterogeneous disease with diverse somatic mutations, and several of them include the so-called driver mutations, which may serve as "druggable" therapeutic targets. Thus, development of personalized approaches for the treatment of non-small cell lung carcinoma (NSCLC) mandates that pathologists make a precise histologic classification inclusive of routine molecular analysis of such tumors.

OBJECTIVE

To address the molecular mechanisms underlying NSCLC and how this knowledge reflects the multidisciplinary approach in the diagnosis and management of these patients. We will also summarize the current available and investigational personalized therapies for patients with resectable early-stage, unresectable locally advanced, and metastatic NSCLC.

DATA SOURCES

Peer-reviewed published literature and personal experience.

CONCLUSIONS

There are multiple mechanisms involved in the pathogenesis of lung cancer, which operate in parallel and involve pathways of activation and inhibition of various cellular events. Further research is essential to characterize the histologic and mutational profiles of lung carcinomas, which will ultimately translate into improved and more personalized therapeutic management of patients with lung cancer.

Molecular genetic testing for lung adenocarcinomas: a practical approach to clinically relevant mutations and translocations

There is a consensus that molecular testing of the lung carcinoma should be the standard of care in the clinical management of patients with lung carcinoma. Recent practice guidelines in oncology and pathology recommend that all advanced and metastatic non-small-cell lung carcinoma with adenocarcinoma histology undergo biomarker testing for epidermal growth factor receptor gene (EGFR) mutations and anaplastic lymphoma kinase gene (ALK) rearrangements. Other types of non-small-cell carcinoma may be considered for such testing if they occur in never-smokers. The landscape of targetable biomarkers in non-small-cell carcinoma is changing rapidly, and demand for clinical testing beyond EGFR mutations and ALK gene rearrangements is increasing. Many patients may test positive for other 'drivers'. As a result, they may be treated with approved biomarker-driven therapies or may be eligible to receive investigational agents in clinical trials. This creates challenges for treating physicians and pathologists such as obtaining sufficient tissue for molecular testing and standardisation of molecular testing in clinical laboratories. This review will focus on the most important lung carcinoma biomarkers predictive of response and will discuss proposed routine molecular testing in clinical practice.

How sensitive are epidermal growth factor receptor-tyrosine kinase inhibitors for squamous cell carcinoma of the lung harboring EGFR gene-sensitive mutations?

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutations are found mostly in adenocarcinoma, and rarely in squamous cell carcinoma (SQC). Little is known about SQC harboring EGFR mutations.

METHODS

Between April 2006 and October 2010, we investigated the incidence of EGFR activating mutations in SQC of the lung using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) was retrospectively evaluated in patients with EGFR-mutated SQC. Further pathologic analyses were performed using immunohistochemistry.

RESULTS

Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%). Twenty of these 33 patients received EGFR-TKI therapy, and five of these 20 responded to EGFR-TKIs with a response rate of 25.0% (95% confidence interval [CI], 8.7%-49.1%). The patients' median progression-free survival and median overall survival were 1.4 months (95% CI, 0.7-5.8 months) and 14.6 months (95% CI, 2.9-undeterminable months), respectively. Approximately one third of the EGFR-mutated SQC patients achieved progression-free survival for longer than 6 months. Some of these patients had high carcinoembryonic antigen levels or a history of never smoking, or were positive for thyroid transcription factor-1.

CONCLUSIONS

Although EGFR-TKIs seem to be generally less effective in EGFR-mutated SQC than in EGFR-mutated adenocarcinoma, some EGFR-mutated SQC patients can obtain clinical benefit from EGFR-TKIs. To better identify these patients, not only EGFR mutation status, but also clinical factors and pathologic findings should be taken into consideration.

Clinicopathological characteristics of EGFR mutated adenosquamous carcinoma of the lung

Adenosquamous carcinoma of the lung (Ad-Sq) is an uncommon subtype with poor prognosis. We analyzed the clinicopathological characteristics of Ad-Sq, focusing the correlation between Epidermal Growth Factor Receptor (EGFR) mutation and clinicopathological factors. A total of 67 cases were selected from September 1992 to May 2011. EGFR mutational analysis (n = 59) was performed by direct sequence. We also performed immunohistochemical staining for EGFR mutated cases using the two mutation-specific antibodies for deletion and L858R. Postoperative 3-year survival rate of Ad-Sq was 58.7%, statistically worse in comparison with adenocarcinoma (58.7% vs. 78.1%, P = 0.038). Twenty-four percent (14/59) were positive for EGFR mutations. Patients who had never been smokers and who were lymphatic permeation positive were seen more frequently in the mutation positive group (P = 0.035, 0.027, respectively). Moreover, the EGFR mutated group tended to have a more positive prognosis than negative. Focusing on the pathological features, the lepidic growth pattern was more frequently seen in the positive group (P = 0.018). Immunoreactivity for the DEL-specific and L858-specific antibody were observed in both adenocarcinoma and squamous cell carcinoma components. Our study demonstrated that EGFR mutated Ad-Sq had similar clinicopathological features as EGFR mutated adenocarcinoma.

Molecular Pathology of Non-Small Cell Lung Cancer

This review offers an overview of the molecular pathology of lung cancer, with a focus on analyses that are most commonly part of the current clinical testing paradigm. Molecular testing of lung cancer has proved integral to the success of new targeted therapies, and their use is now commonplace in treatment selection. Traditional pathologic evaluation, however, plays a major role in these advances and serves an equally critical role to aid in determining optimal therapy.

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.

Targeting of a conformationally exposed, tumor-specific epitope of EGFR as a strategy for cancer therapy

Epidermal growth factor receptor (EGFR) and its most common extracellular mutant, EGFRvIII, are important therapeutic targets in multiple cancer types. A number of monoclonal antibodies and small-molecule inhibitors against these receptors are now used for anticancer treatments. New insights into the structure and function of these receptors illustrate how they can be targeted in novel ways, with expected improvements in the therapeutic efficacy. Monoclonal antibody 806 (mAb806) is an antibody that targets a conformationally exposed epitope of wild-type EGFR when it is overexpressed on tumor cells or in the presence of oncogenic mutations such as EGFRvIII. The mechanism of action of mAb806, which allows for EGFR inhibition without normal tissue toxicity, creates opportunities for combination therapy and strongly suggests mAb806 will be a superior targeted delivery system for antitumor agents. Targeting of the epitope for mAb806 also appears to be an improved strategy to inhibit tumors that express EGFRvIII. This concept of conformational epitope targeting by antibodies reflects an underlying interplay between the structure and biology of different conformational forms of the EGFR family.

Retrospective study of erlotinib in patients with advanced squamous lung cancer

BACKGROUND

The effective targeted therapy for lung squamous cell carcinoma (SCC) is needed. The epidermal growth factor receptor (EGFR) mutation rate is low in lung SCC. The aim of this study was to evaluate the status of erlotinib treatment and EGFR mutation in lung SCC patients.

METHODS

We retrospectively enrolled lung cancer patients with SCC histology and history of erlotinib treatment. The primary objective was to assess overall response rate (ORR) and disease control rate (DCR) and the secondary objective was to assess progression-free survival (PFS) and overall survival (OS). EGFR mutations were assessed in parts of patients using both direct sequencing and protein nucleic acid-locked nucleic acid polymerase chain reaction (PNA-LNA PCR) clamp methods.

RESULTS

In total, 92 patients were analyzed (75 men and 17 women, median age 69 years, and 74 current or former smokers). Sixteen patients achieved partial response and 9 had stable disease. The ORR was 17.4% and the DCR was 27.2%. The PFS and OS were longer in patients with disease control than with progressive disease (PFS 7.8 versus 1.3 months and OS 20.7 versus 2.7 months, both p<0.0001). The 1-year survival rate was 21.7%. In 27 patients with adequate specimens for molecular analysis (including 4 PR and 4 SD), two (7.4%) had EGFR complex mutations. One patient experienced response to erlotinib and the other did not.

CONCLUSIONS

A significant proportion of lung SCC patients would derive a clinical benefit from erlotinib treatment. The relatively higher response rate than the EGFR mutation rate in present study needs further evaluation.

Molecular pathology of lung cancer: key to personalized medicine

The majority of lung adenocarcinoma patients with epidermal growth factor receptor- (EGFR) mutated or EML4-ALK rearrangement-positive tumors are sensitive to tyrosine kinase inhibitors. Both primary and acquired resistance in a significant number of those patients to these therapies remains a major clinical problem. The specific molecular mechanisms associated with tyrosine kinase inhibitor resistance are not fully understood. Clinicopathological observations suggest that molecular alterations involving so-called 'driver mutations' could be used as markers that aid in the selection of patients most likely to benefit from targeted therapies. In this review, we summarize recent developments involving the specific molecular mechanisms and markers that have been associated with primary and acquired resistance to EGFR-targeted therapy in lung adenocarcinomas. Understanding these mechanisms may provide new treatment avenues and improve current treatment algorithms.

Clarifying the spectrum of driver oncogene mutations in biomarker-verified squamous carcinoma of lung: lack of EGFR/KRAS and presence of PIK3CA/AKT1 mutations

PURPOSE

There is persistent controversy as to whether EGFR and KRAS mutations occur in pulmonary squamous cell carcinoma (SQCC). We hypothesized that the reported variability may reflect difficulties in the pathologic distinction of true SQCC from adenosquamous carcinoma (AD-SQC) and poorly differentiated adenocarcinoma due to incomplete sampling or morphologic overlap. The recent development of a robust immunohistochemical approach for distinguishing squamous versus glandular differentiation provides an opportunity to reassess EGFR/KRAS and other targetable kinase mutation frequencies in a pathologically homogeneous series of SQCC.

EXPERIMENTAL DESIGN

Ninety-five resected SQCCs, verified by immunohistochemistry as ΔNp63(+)/TTF-1(-), were tested for activating mutations in EGFR, KRAS, BRAF, PIK3CA, NRAS, AKT1, ERBB2/HER2, and MAP2K1/MEK1. In addition, all tissue samples from rare patients with the diagnosis of EGFR/KRAS-mutant "SQCC" encountered during 5 years of routine clinical genotyping were reassessed pathologically.

RESULTS

The screen of 95 biomarker-verified SQCCs revealed no EGFR/KRAS [0%; 95% confidence interval (CI), 0%-3.8%], four PIK3CA (4%; 95% CI, 1%-10%), and one AKT1 (1%; 95% CI, 0%-5.7%) mutations. Detailed morphologic and immunohistochemical reevaluation of EGFR/KRAS-mutant "SQCC" identified during clinical genotyping (n = 16) resulted in reclassification of 10 (63%) cases as AD-SQC and five (31%) cases as poorly differentiated adenocarcinoma morphologically mimicking SQCC (i.e., adenocarcinoma with "squamoid" morphology). One (6%) case had no follow-up.

CONCLUSIONS

Our findings suggest that EGFR/KRAS mutations do not occur in pure pulmonary SQCC, and occasional detection of these mutations in samples diagnosed as "SQCC" is due to challenges with the diagnosis of AD-SQC and adenocarcinoma, which can be largely resolved by comprehensive pathologic assessment incorporating immunohistochemical biomarkers.

The challenge of NSCLC diagnosis and predictive analysis on small samples. Practical approach of a working group

Until recently, the division of pulmonary carcinomas into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) was adequate for therapy selection. Due to the emergence of new treatment options subtyping of NSCLC and predictive testing have become mandatory. A practical approach to the new requirements involving interaction between pulmonologist, oncologist and molecular pathology to optimize patient care is described. The diagnosis of lung cancer involves (i) the identification and complete classification of malignancy, (ii) immunohistochemistry is used to predict the likely NSCLC subtype (squamous cell vs. adenocarcinoma), as in small diagnostic samples specific subtyping is frequently on morphological grounds alone not feasible (NSCLC-NOS), (iii) molecular testing. To allow the extended diagnostic and predictive examination (i) tissue sampling should be maximized whenever feasible and deemed clinically safe, reducing the need for re-biopsy for additional studies and (ii) tissue handling, processing and sectioning should be optimized. Complex diagnostic algorithms are emerging, which will require close dialogue and understanding between pulmonologists and others who are closely involved in tissue acquisition, pathologists and oncologists who will ultimately, with the patient, make treatment decisions. Personalized medicine not only means the choice of treatment tailored to the individual patient, but also reflects the need to consider how investigative and diagnostic strategies must also be planned according to individual tumour characteristics.

The landscape of EGFR pathways and personalized management of non-small-cell lung cancer

Two classes of anti-EGF receptor (EGFR) agents, monoclonal anti-EGFR antibodies and small-molecule EGFR tyrosine kinase inhibitors, have been used for the treatment of non-small-cell lung cancer (NSCLC). However, only a subset of patients will benefit from EGFR-targeted therapy. The discovery of biomarkers that select the appropriate patients for the therapy and predict the responses to the therapy is urgently needed. Molecular genetic analyses provide new insights into EGFR pathway alterations and demonstrate promise for predicting the clinical outcome of patients with NSCLC. In this article, we summarize the latest available knowledge on the clinical impact of EGFR mutations, gene copy number, EGFR overexpression, phosphorylation expression and the alteration of the EGFR pathway downstream factors in predicting the response to EGFR-targeted therapy in NSCLC patients. The role of KRAS and BRAF mutations and ALK rearrangement in lung cancer-targeted therapy, are also reviewed.

Emerging concepts in the pathology and molecular biology of advanced non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is traditionally classified histologically, but until recently, the histologic subtype has had little impact on the selection of therapy. Drugs such as pemetrexed and bevacizumab are indicated for specific NSCLC subtypes, and this type of stratification represents the first step toward individualizing therapy in NSCLC. Beyond histologic features, the status of molecular targets, such as the epidermal growth factor receptor (EGFR) gene, has been shown to correlate with response to treatment with EGFR tyrosine kinase inhibitors in patients with relapsed or refractory disease and in the first-line therapy setting. New therapies targeting the EGFR and other molecular aberrations are under way to help define specific subsets of patients responsive to certain molecularly targeted treatments. The role of pathologists in guiding treatment decisions will increase because molecular profiling, together with pathologic and histologic analysis, represents the future of personalizing medicine for patients with NSCLC.

Adenosquamous carcinoma of the lung: a microdissection study of KRAS and EGFR mutational and amplification status in a western patient population

Molecular testing of pulmonary adenocarcinomas for EGFR and KRAS mutations is becoming more common as tyrosine kinase inhibitor therapy is used for EGFR-mutated adenocarcinomas. Adenosquamous carcinomas represent a hybrid carcinoma, and there is no literature addressing the frequency of EGFR and KRAS mutations in this subset of lung carcinomas in Western populations. For this study, 23 adenosquamous carcinomas were microdissected with the glandular and squamous components analyzed for EGFR and KRAS mutations and EGFR amplification. In 3 cases (13%), there were EGFR mutations, with 2 having the identical mutation in the glandular and squamous elements. In 3 cases (13%), there were KRAS mutations in both histologic elements. Great heterogeneity existed in the rates of EGFR amplification in the 2 histologic components. Amplification was most common in both glandular and squamous components (11/23 [48%]). EGFR mutations occur in adenosquamous carcinoma in the same percentages as in conventional adenocarcinoma in the Western population. KRAS mutations are less common.

Imaging of lung cancer in the era of molecular medicine

Recent discoveries characterizing the molecular basis of lung cancer brought fundamental changes in lung cancer treatment. The authors review the molecular pathogenesis of lung cancer, including genomic abnormalities, targeted therapies, and resistance mechanisms, and discuss lung cancer imaging with novel techniques. Knowledge of the molecular basis of lung cancer is essential for radiologists to properly interpret imaging and assess response to therapy. Quantitative and functional imaging helps assessing the biologic behavior of lung cancer.

Downregulated ABCG2 enhances sensitivity to topoisomerase I inhibitor in epidermal growth factor receptor tyrosine kinase inhibitor-resistant non-small cell lung cancer

INTRODUCTION

Understanding the mechanisms of drug resistance to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) is essential to develop novel chemotherapies for non-small cell lung cancer (NSCLC). Therefore, we analyzed the expression and function of ATP-binding cassette (ABC) transporters in EGFR TKI-resistant NSCLC.

METHODS

In three newly established AG1478-resistant NSCLC cell lines, we evaluated the expression profile of ABC transporters and genotyping of ABCG2 by real-time polymerase chain reaction and elucidated their function by Hoechst dye efflux analyses. The growth-inhibitory effect of the topoisomerase I inhibitor Hoechst 33342, which is extruded by ABCG2, was also investigated in these cells using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay.

RESULTS

In AG1478-resistant cells, significantly less ABCG2 was expressed, and the ratios of the cells with a strong ability to extrude Hoechst dye were remarkably smaller than in the parent cells. Because of the ABCG2 downregulation and loss of function due to C421A/C421A homozygosity, PC-14AG50R was thus considered to be more sensitive to Hoechst 33342 than the parental cells. All AG1478-resistant cells were more sensitive to the combination of Hoechst 33342 and AG1478 than to single agent.

CONCLUSIONS

Resistance to EGFR TKI in NSCLC is associated with the downregulation of ABCG2 expression. A topoisomerase I inhibitor alone or in combination with EGFR TKI might offer a promising strategy for treating NSCLC that is resistant to EGFR TKI.

Survival comparison of adenosquamous, squamous cell, and adenocarcinoma of the lung after lobectomy

BACKGROUND

Primary adenosquamous carcinoma (ASC) of the lung is a rare tumor that may carry a poor prognosis. We examined a national database to see if ASC exhibited distinct clinical behavior from squamous cell (SC) and adenocarcinoma (AC) of the lung.

METHODS

This is a retrospective study querying the Surveillance, Epidemiology, and End Results database to identify 872 surgical patients diagnosed with ASC, 7888 with SC, and 12,601 with AC of the lung from 1998 to 2002. Analysis characterized clinical variables to determine patterns of presentation and compared survival among the above three histologic groups after lobectomy for stage I and II disease.

RESULTS

ASC represented 4.1% of the 21,361 patients examined. ASC tended toward right side (56.9%) laterality and upper lobe (60.0%) location. Compared with AC, patients with ASC and SC were more likely to be male (p < 0.0001), and ASC patients had worse histologic grade (p< 0.0001). Survival after lobectomy for stage I and II disease was significantly reduced in ASC and SC compared with AC (p < 0.0001). ASC had a significantly increased hazard ratio of 1.35 and 1.27 relative to AC and SC, respectively. Other significant negative predictors of survival included tumor grade of III and IV, stage II, age, and black ethnicity.

CONCLUSIONS

This large review demonstrates that ASC is an uncommon tumor with distinct clinical behavior and worse prognosis than AC and SC. Further insight into the molecular profile of ASC is needed to determine the cause of its biologic aggressiveness.