Identical epidermal growth factor receptor mutations in adenocarcinomatous and squamous cell carcinomatous components of adenosquamous carcinoma of the lung

Primary versus acquired epidermal growth factor receptor Thr790Met mutant non-small cell lung cancer: clinical features and prognoses

PURPOSE

This study aimed to identify the impact of epidermal growth factor receptor (EGFR) T790M mutations on clinical characteristics and prognosis.

METHODS

Retrospective analyses were conducted on the differences on clinicopathological features and prognosis between primary and acquired T790M mutations. Subgroup analyses were performed for primary T790M coexisting with other mutations.

RESULTS

Patients with primary T790M mutations showed a 60.53% (23/38) incidence of concurrent L858R mutations, 18.42% (7/38) for 19del mutations and a 21.05% (8/38) occurrence of brain metastases. Conversely, those with acquired T790M mutations demonstrated respective frequencies of 36.53% (61/167), 58.68% (98/167) and 44.31% (74/167), with all comparisons yielding p < 0.05. The median overall survival differed significantly between the two groups, with a duration of 33 months for patients with primary T790M mutations as compared to 48 months for those with acquired mutations (p = 0.030). Notably, among patients with L858R co-mutations, when treated with third-generation EGFR-TKIs, those with acquired T790M mutations experienced a significantly prolonged median time to treatment failure compared to those with primary mutations (17 months vs. 9 months, p = 0.009).

CONCLUSION

Patients with primary T790M have unique molecular features and had worse prognosis compared with acquired T790M. Resistance to third-generation EGFR-TKIs seems to be associated with the presence of EGFR co-mutations.

Clonal dynamics and Stereo-seq resolve origin and phenotypic plasticity of adenosquamous carcinoma

The genomic origin and development of the biphasic lung adenosquamous carcinoma (ASC) remain inconclusive. Here, we derived potential evolutionary trajectory of ASC through whole-exome sequencing, Stereo-seq, and patient-derived xenografts. We showed that EGFR and MET activating mutations were the main drivers in ASCs. Phylogenetically, these drivers and passenger mutations found in both components were trunk clonal events, confirming monoclonal origination. Comparison of multiple lesions also revealed closer genomic distance between lymph node metastases and the ASC component with the same phenotype. However, as mutational signatures of EGFR-positive lung squamous carcinomas (LUSCs) were more comparable to EGFR-positive ASCs than to wild-type LUSCs, we postulated different origination of these LUSCs, with ASC being the potential intermediate state of driver-positive LUSCs. Spatial transcriptomic profiling inferred transformation from adenocarcinoma to squamous cell carcinoma, which was then histologically captured in vivo. Together, our results explained the development of ASC and provided insights into future clinical decisions.

Case Report: Response to ALK-TKIs in a metastatic lung cancer patient with morphological heterogeneity and consistent molecular features

Lung adenosquamous carcinoma (ASC) is a rare heterogeneous tumor containing two distinct components of adenocarcinoma (ADC) and squamous cell carcinoma (SQCC). The limited biopsy sampling of the primary tumor might have overlooked either the ADC component or the SQCC component, resulting in a misdiagnosis of pure histology. Genotyping for driver mutations is now routinely performed in clinical settings to identify actionable oncogenic mutations and gene arrangements. Additionally, somatic mutations can potentially serve as a marker of clonal relationships. We report a rare case of ASC lung cancer, in which metastases were identified as ADC, while the primary was initially diagnosed as SQCC based on a fibrobronchoscope brush biopsy. The primary and metastatic tumors shared ALK rearrangement and other mutations support they were derived from a single clone origin. Our hypothesis is that the primary tumor contained a minor component of ADC that was not present in the histologic sections of lung biopsy. After sequential ALK-tyrosine kinase inhibitor (TKI) targeted therapy, both the patient's primary lung tumor and the site of metastatic subcutaneous nodules decreased in size, with the metastatic sites demonstrating more noticeable shrinkage. However, after 11 months of targeted therapy, the patient was found to be resistant to ALK-TKIs. Subsequently, the patient's respiratory status deteriorated rapidly, and a cycle of immunotherapy and chemotherapy did not show efficacy. To the best of our knowledge, this is a very rare case of lung ASC, disseminated metastasizing, with distinct morphology between the primary and metastases. Different therapeutic effects of ALK-TKIs were observed in two different morphological sites, with the metastatic cutaneous lesions shrinking more significantly than the primary lung lesions, though they both harbor the same EML4-ALK rearrangement. This case may provide diagnostic and therapeutic insights into lung ASC.

Adenosquamous Carcinomas and Mucinous Adenocarcinoma of the Minor Salivary Glands: Immunohistochemical and Molecular Insights

There is confusion about the diagnosis, histogenesis and taxonomical efforts regarding adenosquamous carcinomas (ASCs) and mucinous adenocarcinomas (MACs), especially with calls for reconsidering the nature of high-grade mucoepidermoid carcinoma (MEC). This study aims to compare the genetic profiles of ASCs and MACs that have been previously reported in the literature and investigate if either ASC or MAC is closer in genetic mutations to high-grade MEC. Systematic searches in the NCBI, Web of Science, and Scopus databases were performed between January 2000 and August 2022. The retrieved genetic mutations were processed and annotated. Protein–protein network analysis was conducted for each neoplasm. The results were viewed and discussed in terms of molecular oncogenesis of ASCs and MACs at different topographies. Molecular profile mapping was conducted by annotating all the retrieved genes for each neoplasm using genetic network analysis (Cystoscape software program). The genetic profile of each lesion was compared to that of high-grade MEC. To conclude, both genetic profiles do not tend to intersect specifically with high-grade MEC, except for the generic mutations commonly detected in all high-grade head and neck tumors. However, the availability of data on the molecular profile of each lesion limits the generalizability of the findings of this study.

Heterogeneity of tumor immune microenvironment and real-world analysis of immunotherapy efficacy in lung adenosquamous carcinoma

Lung adenosquamous carcinoma (ASC) is an uncommon histological subtype. We aimed to characterize the tumor immune microenvironment (TIME) in lung ASC and estimate patient response to immune checkpoint inhibitors (ICIs), which have never been systematically investigated. In cohort I, we collected 30 ASCs from a single center for analysis of TIME characteristics, including immuno-phenotyping, tumor mutation burden (TMB), T-cell receptor (TCR) repertoires, tumor-infiltrating lymphocytes (TILs), and immune checkpoint expression. Twenty-two (73.3%) patients were EGFR-positive. The TIME was defined by immune-excluded (60%) and immune-desert phenotype (40%). Strikingly, programmed cell death-ligand 1 (PD-L1) and programmed cell death-1 (PD-1) were predominantly expressed in squamous cell carcinoma components (SCCCs) versus adenocarcinoma components (ACCs), where enhanced CD4⁺ FOXP3⁺ regulatory T cell and attenuated CD57⁺ natural killer cell infiltration were present, consistent with a landscape of fewer innate immune cells, more immunosuppressive cells. SCCCs had higher TMB, higher TCR clonality, and lower TCR diversity than ACC. In cohort III, the efficacy of ICI-based therapy was estimated using a real-world data of 46 ASCs from 11 centers. Majority of 46 patients were driver genes negative and unknown mutation status, 18 (39%) and 18 (39%), respectively. The overall objective response rate of 28%, median progression-free survival of 6.0 months (95% confidence interval [CI] 4.3–7.7), and median overall survival of 24.7 months (95% CI 7.2–42.2) were observed in the ICI-based treatment. This work ascertains suppressive TIME in lung ASC and genetic and immuno-heterogeneity between ACCs and SCCCs. Lung ASC patients have a moderate response to ICI-based immunotherapy.

Clinicopathological characteristics and prognosis of resectable lung adenosquamous carcinoma: a population-based study of the SEER database

OBJECTIVE

Adenosquamous carcinoma is a rare subtype of non-small cell lung cancer characterized by aggressive behavior, with combination of adenocarcinoma and squamous cell carcinoma components. The clinicopathological characteristics and prognosis of resectable adenosquamous carcinoma are incompletely understood and this study aimed to depict those in a large population.

METHODS

A total of 805 adenosquamous carcinoma, 7875 squamous cell carcinoma and 23 957 adenocarcinoma patients who underwent lobectomy or sublobectomy were queried from the Surveillance, Epidemiology, and End Results database (2010-17). Clinicopathological characteristics of adenosquamous carcinoma patients were compared with those of squamous cell carcinoma and adenocarcinoma patients. Prognostic factors were identified by univariable and multivariable Cox regression analyses. Propensity score matching was applied to reduce confounding effects.

RESULTS

Adenosquamous carcinoma was associated with higher pleural invasion incidence and poorer differentiation compared with squamous cell carcinoma or adenocarcinoma (P values < 0.001). The independent risk factors of cancer-specific survival of adenosquamous carcinoma patients were increasing age, male sex, invading through visceral pleura, poor differentiation and higher stage. Stage IB adenosquamous carcinoma patients whose tumor invaded through visceral pleura had significantly worse survival than those not (P = 0.003). Adenosquamous carcinoma patients had worse survival compared with squamous cell carcinoma (5-year-survival: 64.55 vs. 69.09%, P = 0.003) and adenocarcinoma (5-year-survival: 64.55 vs. 76.79%, P < 0.001) patients before match. And this difference persisted after match.

CONCLUSIONS

Resectable adenosquamous carcinoma patients had higher pleural invasion incidence, poorer differentiation and worse survival compared with squamous cell carcinoma and adenocarcinoma patients. Visceral pleural invasion status and differentiation grade were vital prognostic factors of adenosquamous carcinoma patients on the basis of stage.

The histologic phenotype of lung cancers is associated with transcriptomic features rather than genomic characteristics

Histology plays an essential role in therapeutic decision-making for lung cancer patients. However, the molecular determinants of lung cancer histology are largely unknown. We conduct whole-exome sequencing and microarray profiling on 19 micro-dissected tumor regions of different histologic subtypes from 9 patients with lung cancers of mixed histology. A median of 68.9% of point mutations and 83% of copy number aberrations are shared between different histologic components within the same tumors. Furthermore, different histologic components within the tumors demonstrate similar subclonal architecture. On the other hand, transcriptomic profiling reveals shared pathways between the same histologic subtypes from different patients, which is supported by the analyses of the transcriptomic data from 141 cell lines and 343 lung cancers of different histologic subtypes. These data derived from mixed histologic subtypes in the setting of identical genetic background and exposure history support that the histologic fate of lung cancer cells is associated with transcriptomic features rather than the genomic profiles in most tumors.

The molecular determinants of lung cancer histologic subtypes are not well understood. Here the authors analyze lung cancers of mixed histology and find that histologic subtypes are associated with transcriptomic features rather than genomic profiles in most tumors.

LKB1 and cancer: The dual role of metabolic regulation

Liver kinase B1 (LKB1) is an essential serine/threonine kinase frequently associated with Peutz-Jeghers syndrome (PJS). In this review, we provide an overview of the role of LKB1 in conferring protection to cancer cells against metabolic stress and promoting cancer cell survival and invasion. This carcinogenic effect contradicts the previous conclusion that LKB1 is a tumor suppressor gene. Here we try to explain the contradictory effect of LKB1 on cancer from a metabolic perspective. Upon deletion of LKB1, cancer cells experience increased energy as well as oxidative stress, thereby causing genomic instability. Meanwhile, mutated LKB1 cooperates with other metabolic regulatory genes to promote metabolic reprogramming that subsequently facilitates adaptation to strong metabolic stress, resulting in development of a more aggressive malignant phenotype. We aim to specifically discuss the contradictory role of LKB1 in cancer by reviewing the mechanism of LKB1 with an emphasis on metabolic stress and metabolic reprogramming.

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.

Diffusion tensor and postcontrast T1-weighted imaging radiomics to differentiate the epidermal growth factor receptor mutation status of brain metastases from non-small cell lung cancer

PURPOSE

To assess whether the radiomic features of diffusion tensor imaging (DTI) and conventional postcontrast T1-weighted (T1C) images can differentiate the epidermal growth factor receptor (EGFR) mutation status in brain metastases from non-small cell lung cancer (NSCLC).

METHODS

A total of 99 brain metastases in 51 patients who underwent surgery or biopsy with underlying NSCLC and known EGFR mutation statuses (57 from EGFR wild type, 42 from EGFR mutant) were allocated to the training (57 lesions in 31 patients) and test (42 lesions in 20 patients) sets. Radiomic features (n = 526) were extracted from preoperative MR images including T1C and DTI. Radiomics classifiers were constructed by combinations of five feature selectors and four machine learning algorithms. The trained classifiers were validated on the test set, and the classifier performance was assessed by determining the area under the curve (AUC).

RESULTS

EGFR mutation status showed an overall discordance rate of 12% between the primary tumors and corresponding brain metastases. The best performing classifier was a combination of the tree-based feature selection and linear discriminant algorithm and 5 features were selected (1 from ADC, 2 from fractional anisotropy, and 2 from T1C images), resulting in an AUC, accuracy, sensitivity, and specificity of 0.73, 78.6%, 81.3%, and 76.9% in the test set, respectively.

CONCLUSIONS

Radiomics classifiers integrating multiparametric MRI parameters may have potential in differentiating the EGFR mutation status in brain metastases from NSCLC.

A nomogram to predict prognosis of patients with lung adenosquamous carcinoma: a population-based study

Background

Adenosquamous carcinoma (ASC) of the lung is an infrequent variant of lung cancer. This study aimed to identify independent risk factors and to develop a predictive model for the prognosis of ASC patients.

Methods

Patient data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database (2004 to 2016) and database in our department (2010 to 2014). Overall survival (OS) was evaluated by the Kaplan-Meier method. Significant prognostic factors were identified by univariate analysis (UVA) and multivariate analysis (MVA) using the Cox proportional hazards regression. Competing risk model analyses were performed using cancer-specific survival outcomes. A nomogram was developed to predict patient 3-year and 5-year OS and was validated using data from the two databases.

Results

A total of 4,600 patients with ASC were included and divided into a training cohort (n=3,202) and two validation cohorts (n=1,372, n=26). Patients with ASC had significantly older age, lower grades of tumor differentiation or incidences of nodal, and distant invasions than adenocarcinoma and squamous cell carcinoma (SCC) of the lung (P<0.001), while the median survival time of ASC patients was intermediate [21.0 (19.3-22.7) months]. Age, sex, primary site of tumor, histological grade, T stage, N stage, M stage of the tumor, as well as surgery to the primary tumor site and chemotherapy were identified as independent factors for ASC (P<0.001). A reliable nomogram was established with a group of validation plots and concordance indices (C-indices) (internal: 0.755±0.010; external: 0.748±0.049 and 0.721±0.045).

Conclusions

Age, sex, primary site of tumor, histological grade, T stage, N stage, M stage of the tumor, as well as surgery to the primary site of tumors and chemotherapy were independent risk factors for ASC patients. A validated nomogram was constructed to predict the prognosis based on the patient clinical characteristics.

Clinical Outcomes of Different Generations of EGFR Tyrosine Kinase Inhibitors in Advanced Lung Adenosquamous Carcinoma

OBJECTIVES

The role of targeted therapy in patients with lung adenosquamous carcinoma (ASC) has been controversial and it was unclear whether a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) could improve outcomes. This study was designed to evaluate the efficacy of different generations of EGFR TKI therapy in ASC patients with sensitive EGFR mutations.

METHODS

Patients with non-small cell lung cancer (NSCLC) diagnosed at the Shanghai Chest Hospital between January 2010 and December 2016 were retrospectively reviewed.

RESULTS

A total of 10,037 NSCLC patients tested for EGFR mutations were screened, with primary ASC accounting for 1.4% (139/10,037). Positive EGFR mutations were found in 51.1% (71/139) of ASC patients, including 67 sensitive mutations (19del or 21L858R) and four uncommon mutations (19del + 20T790M, 21L858R + 20T790M, 19L747P + 20Q787Q, and 21L861Q). Sensitive EGFR mutations occurred more frequently in younger (62.0 vs 65.0, p = 0.010), non-smoking (83.6% vs 57.8%, p = 0.002) women (56.7% vs 34.4%, p = 0.014). Among the 36 ASC patients with eligible survival data for the first-generation TKIs, the median progression-free survival (PFS) was 9.3 months (95% CI 6.7-11.9), which was rather similar to the data of adenocarcinoma (9.3 vs 11.4 months, p = 0.294) in our institution as opposed to squamous cell carcinoma (9.3 vs 4.9 months, p < 0.001). The objective response rate (ORR) was 37.9% (11/29), and the disease control rate (DCR) was 86.2% (25/29). After progression on the initial EGFR TKIs, 42.1% of the cases (8/19) had an EGFR T790M mutation detected. A median PFS of 10.2 months (95% CI 5.8-14.5, n = 8) was achieved with treatment using the third-generation TKI. The ORR and DCR were 37.5% (3/8) and 100% (8/8), respectively. The median overall survival reached 38.3 months (95% CI 13.7-62.9).

CONCLUSIONS

Targeted therapy showed remarkable efficacy in ASC patients harboring sensitive EGFR mutations, comparable to adenocarcinoma. The application of the third-generation TKI provided an option to prolong survival.

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.

EGFR mutation exists in squamous cell lung carcinoma

Whether EGFR mutation occurs in lung squamous cell carcinoma (SCC) remains a controversial issue. Although numerous trials have shown positive response to tyrosine kinase inhibitors in SCC, these observations have not been well correlated with presence or absence of EGFR mutation. A complicating issue is that adenosquamous carcinoma, a mimic of SCC, frequently harbours EGFR mutations. We evaluated the EGFR mutation status of 191 cases initially diagnosed as SCC of lung origin in years 2000-2011, and performed a panel of markers including p40, p63, CK5/6, TTF-1, mucicarmine on the tissue microarray or tissue blocks from each case, to ascertain the squamous differentiation of each case. Four cases were found to have EGFR mutations, with three showing typical squamous morphological features and immunohistochemical profile on all available tumour blocks, and one reclassified as adenosquamous carcinoma. Mixed responses were noted for two of the patients with EGFR-mutated SCC treated with tyrosine kinase inhibitors. In conclusion, we report that a small subset of rigorously proven SCC harbours EGFR mutation. It also appears in our cohort that EGFR-mutated tumours, in the context of SCC, may have relatively poor response to tyrosine kinase inhibitors.

Genomic origin and EGFR-TKI treatments of pulmonary adenosquamous carcinoma

BACKGROUND

Adenosquamous carcinoma (ASC) of the lung is a heterogeneous disease that is composed of both adenocarcinoma components (ACC) and squamous cell carcinoma components (SCCC). Their genomic profile, genetic origin, and clinical management remain controversial.

PATIENTS AND METHODS

Resected ASC and metastatic tumor in regional lymph nodes (LNs) were collected. The ACC and SCCC were separated by microdissection of primary tumor. The 1021 cancer-related genes were evaluated by next-generation sequencing independently in ACC and SCCC and LNs. Shared and private alterations in the two components were investigated. In addition, genomic profiles of independent cohorts of adenocarcinomas and squamous cell carcinomas were examined for comparison. We have also carried out a retrospective study of ASCs with known EGFR mutation status from 11 hospitals in China for their clinical outcomes.

RESULTS

The most frequent alterations in 28 surgically resected ASCs include EGFR (79%), TP53 (68%), MAP3K1 (14%) mutations, EGFR amplifications (32%), and MDM2 amplifications (18%). Twenty-seven patients (96%) had shared variations between ACC and SCCC, and pure SCCC metastases were not found in metastatic LNs among these patients. Only one patient with geographically separated ACC and SCCC had no shared mutations. Inter-component heterogeneity was a common genetic event of ACC and SCCC. The genomic profile of ASC was similar to that of 170 adenocarcinomas, but different from that of 62 squamous cell carcinomas. The incidence of EGFR mutations in the retrospective analysis of 517 ASCs was 51.8%. Among the 129 EGFR-positive patients who received EGFR-TKIs, the objective response rate was 56.6% and the median progression-free survival was 10.1 months (95% confidence interval: 9.0-11.2).

CONCLUSIONS

The ACC and SCCC share a monoclonal origin, a majority with genetically inter-component heterogeneity. ASC may represent a subtype of adenocarcinoma with EGFR mutation being the most common genomic anomaly and sharing similar efficacy to EGFR TKI.

A 38-Year-Old Man With An Ataxic Gait, Night Sweats, and Weight Loss

CASE PRESENTATION

A 38-year-old Jamaican man with no medical history presented with worsening right-sided weakness. He developed an ascending hemiparesis that began in the right lower extremity 3 months ago and progressed to the right upper extremity this past month. Over the past 3 months, the patient has had unintentional weight loss and an ataxic gait, and for the past month he has had night sweats. He denied headache, vision changes, numbness, tingling, cough, or chest pain. Social history was significant for 20 smoking pack-years and daily use of marijuana.

Pathological transition as the arising mechanism for drug resistance in lung cancer

Despite the tremendous efforts for improving therapeutics of lung cancer patients, its prognosis remains disappointing. This can be largely attributed to the lack of comprehensive understanding of drug resistance leading to insufficient development of effective therapeutics in clinic. Based on the current progresses of lung cancer research, we classify drug resistance mechanisms into three different levels: molecular, cellular and pathological level. All these three levels have significantly contributed to the acquisition and evolution of drug resistance in clinic. Our understanding on drug resistance mechanisms has begun to change the way of clinical practice and improve patient prognosis. In this review, we focus on discussing the pathological changes linking to drug resistance as this has been largely overlooked in the past decades.

A co-expressed gene status of adenylate kinase 1/4 reveals prognostic gene signature associated with prognosis and sensitivity to EGFR targeted therapy in lung adenocarcinoma

Cancer cells utilize altered bioenergetics to fuel uncontrolled proliferation and progression. At the core of bioenergetics, adenine nucleotides are the building blocks for nucleotide synthesis, energy transfer and diverse metabolic processes. Adenylate kinases (AK) are ubiquitous phosphotransferases that catalyze the conversion of adenine nucleotides and regulate the homeostasis of nucleotide ratios within cellular compartments. Recently, different isoforms of AK have been shown to induce metabolic reprograming in cancer and were identified as biomarkers for predicting disease progression. Here we aim to systemically analyze the impact of all AK-associated gene signatures on lung adenocarcinoma patient survival and decipher the value for therapeutic interventions. By analyzing TCGA Lung Adenocarcinoma (LUAD) RNA Seq data, we found gene signatures from AK4 and AK1 have higher percentage of prognostic genes compared to other AK-gene signatures. A 118-gene signature was identified from consensus gene expression in AK1 and AK4 prognostic gene signatures. Immunohistochemistry (IHC) analyses in 140 lung adenocarcinoma patients showed overexpression of AK4 significantly correlated with worse overall survival (P = 0.001) whereas overexpression of AK1 significantly associated with good prognosis (P = 0.009). Furthermore, reduced AK4 expression by shRNA reduced the EGFR protein expression in EGFR mutation cells. The inhibition of AK4-AK1 signal might provide a potential target for synergistic effect in target therapy in lung cancer patients.

Uncommon Types of Lung Carcinoma With Mixed Histology: Sarcomatoid Carcinoma, Adenosquamous Carcinoma, and Mucoepidermoid Carcinoma

CONTEXT

- Lung tumors are histologically heterogeneous, but classification of lung carcinoma has prognostic impact and increasingly, specific molecular correlates.

OBJECTIVE

- To update the gross, microscopic, and molecular pathology of unusual lung carcinomas to assure accurate classification. In entities with mixed histology, the recognition of specific features or rare patterns is critical to diagnosis. These diagnoses can identify tumors with aggressive clinical behavior, and diagnostic pitfalls can therefore result in underdiagnosis of these already rare entities. Incorrect classification of more indolent tumors into the more aggressive categories can also occur. In the area of molecular pathology, these unusual tumors have a specific spectrum of molecular alterations.

DATA SOURCES

- PubMed searches for lung and sarcomatoid carcinoma, pleomorphic carcinoma, blastoma, carcinosarcoma, and adenosquamous and mucoepidermoid carcinoma were undertaken and this information was integrated with clinical experience of the author.

CONCLUSIONS

- These uncommon carcinomas have specific clinicopathologic features, and attention to their gross and microscopic pathology leads to classification with important associated molecular findings.

The importance of EGFR mutation testing in squamous cell carcinoma or non-small cell carcinoma favor squamous cell carcinoma diagnosed from small lung biopsies

Background

Adenosquamous carcinoma (ADSC) of the lung, a rare but aggressive subtype of non-small cell lung cancer (NSCLC), is defined as a carcinoma containing components of adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). Mutations of epidermal growth factor receptor (EGFR) are found at a frequency of 15 to 44% in Asian ADSC, and EGFR tyrosine kinase inhibitors (EGFR-TKIs) are a more effective treatment for EGFR-mutated ADSC compared to chemotherapy. However, ADSC in small lung biopsies could be misdiagnosed as SqCC or non-small cell carcinoma (NSCC) favor SqCC due to undersampling, which may result in neglecting of EGFR mutation testing and affecting patients’ clinical management, particularly in Asian patients that relatively have high prevalence of EGFR mutation.

Methods

A total of 148 small lung biopsy cases with pathological diagnosis of SqCC or NSCC favor SqCC were retrospectively enrolled. The frequency of EGFR mutations and the correlation between patients’ EGFR mutation status and clinicopathological characteristics were evaluated.

Results

EGFR mutations were found in 8.8% (13 /148) of all cases with 5.2% (7/135) in SqCC and 46.2% (6/13) in NSCC favor SqCC. There were 7 (53.8%) L858R mutation, 4 (30.8%) exon 19 deletions, and 2 (15.4%) cases with coexistent L858R and T790 M mutations. Multivariate analysis showed that EGFR mutations were more prevalent in never-smokers (83.3% versus 16.7%, p = 0.006) and patients diagnosed as NSCC favor SqCC (46.2% versus 5.2%, p = 0.001). Moreover, 75% (3/4) of EGFR mutation-positive cases with subsequent surgical resection or rebiopsy were further diagnosed as ADSC.

Conclusions

EGFR mutation testing should be performed in Asian patients with SqCC diagnosed from small lung biopsies, especially in never-smokers and patients with diagnosis of NSCC favor SqCC, which have a high probability of being ADSC.

Identification of Adenosquamous Carcinoma as a Rare Aggressive HER2-negative Subgroup of Esophageal/Gastroesophageal Junction Adenocarcinoma

BACKGROUND

Our purpose was to evaluate the prognostic impact of pathologically confirmed esophageal adenosquamous carcinoma (ASC) and its association with HER2 status and clinicopathologic characteristics.

METHODS

Among 796 patients with esophageal or gastroesophageal junction adenocarcinoma who underwent curative resection, surgical pathology reports were reviewed, and suspected ASC was confirmed utilizing p63 and CK5/6 immunostaining. HER2 status was determined using immunohistochemistry and fluorescence in situ hybridization. Cox models were used to assess the impact of ASC on disease-specific survival and overall survival.

RESULTS

Overall, 2.0% (16/796) of patients had esophageal ASC, mostly demonstrating a close intermingling of squamous and adenocarcinoma cells within the same tumor. The percentage of squamous versus adenocarcinoma cells in the primary was generally recapitulated in nodal metastases, and intrapatient internodal heterogeneity was uncommon. Patients with esophageal ASC were statistically significantly more likely to be female (vs. male), have normal (vs. excess) body mass index, and harbor HER2-negative (vs. positive) tumors, as compared with patients with adenocarcinoma only. No ASC tumor was HER2-positive as compared with 16% of adenocarcinoma only tumors (P=0.018). Compared with patients with adenocarcinoma only, those with ASC demonstrated profoundly worse disease-specific survival (5-year event-free rate, 34% vs. 6%; multivariate hazard ratio, 2.87 [95% confidence interval, 1.59-4.76]; P=0.0010) and overall survival (P=0.0027) that was independent of known prognostic factors and HER2 status.

CONCLUSION

ASC identifies a rare aggressive HER2-negative subgroup of esophageal/gastroesophageal junction adenocarcinoma.

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.

Clinicopathological and genomic comparisons between different histologic components in combined small cell lung cancer and non-small cell lung cancer

OBJECTIVE

Histologic transformation from adenocarcinoma to small cell lung cancer (SCLC) is one of the mechanisms of acquired resistance after epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment. Furthermore, de novo combined SCLC/non-small cell lung cancer (NSCLC) have occasionally been reported; however, their mutational statuses and clinicopathological features have not yet been elucidated. In this study, we aimed to profile the genetic backgrounds of these 2 different histologic components by investigating patients with de novo combined SCLC/NSCLC as well as those with lung adenocarcinoma who experienced SCLC transformation after TKI treatment.

MATERIALS AND METHODS

Four patients with de novo combined SCLC/NSCLC were investigated, as were 4 other patients with lung adenocarcinoma who experienced SCLC transformation after TKI treatment. The different histologic components of the tumors in each patient were tested for thyroid transcription factor-1, p40, synaptophysin, chromogranin A, p53, retinoblastoma protein (Rb), and achaete-scute homolog 1 (ASCL1) via immunohistochemistry, and were macroscopically dissected for mutational analysis using next-generation sequencing with the Oncomine Focus Assay and Comprehensive Assay panel.

RESULTS

The distinct histologic components in patients with de novo combined SCLC/NSCLC and those with adenocarcinoma exhibiting small cell transformation showed high consistency in EGFR/TP53/RB1 mutations, and expression patterns of p53 and Rb. A high frequency of activating mutations involving PI3K/AKT1 signaling pathway was observed in SCLC. Nuclear ASCL1 expression was present in SCLC but absent or barely present in adenocarcinoma in 7 cases.

CONCLUSIONS

Our data imply that inactivation of TP53/RB1 function is a possible early event in the histogenesis of synchronous and metachronous SCLC/NSCLC. Moreover, the non-adenocarcinoma (SCLC) component might arise from the adenocarcinoma (NSCLC) component through a mechanism that involves the activation of the ASCL1 and PI3K/AKT1 signaling pathways.

Adenosquamous carcinoma of the lung

Adenosquamous carcinoma of the lung (ASC), a relatively rare subtype of non-small-cell lung cancer, is defined as a malignancy containing components of lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SCC). Although ASC has biological characteristics of ADC and SCC, it is not by any means a simple hybrid of two components above. It is extremely difficult to diagnose preoperatively; pathology of surgically resected gross specimen is the most effective means for adequate diagnosis of ASC. Platinum-based postoperative adjuvant chemotherapy for at least four cycles can significantly improve the survival in stage III patients with ASC. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as erlotinib and gefitinib can be the effective therapeutic strategies for advanced EGFR-mutant ASC. The studies of crizotinib in the treatment of patients with ASC are very limited. Immune checkpoint blockade therapy may be a potential treatment choice for ASC patients.

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 characteristics and prognosis of patients with lung adenosquamous carcinoma after surgical resection: results from two institutes

Background

Adenosquamous carcinoma (ASC) is a mixed glandular and squamous cell carcinoma (SCC) with more aggressive behavior than the other histologic subtypes of lung cancer. We aim to evaluate the prognosis of patients with ASC after surgical resection.

Methods

We reviewed records of patients who underwent surgical resection for lung cancer in two institutes between January 2010 and December 2015. Survival data were collected with a median follow-up of 59 (range from 10 to 85) months. Kaplan-Meier survival curve was determined for all patients.

Results

Patients with ASC accounted for 1.6% of all NSCLC patients (33 males, 25 females). The cumulative postoperative 3- and 5-year survival rates were 56% and 48%, respectively. Overall survival (OS) was significantly lower in ASC patients than in adenocarcinoma (AC) patients operated during the same period (P<0.01). Patients with ASC containing acinar predominant AC had better survival than those with non-acinar predominant ASC (P=0.03). No difference of OS was found in patients with or without visceral pleural invasion (VPI), vascular invasion (VI) or EGFR mutation status. Multivariate analysis showed gender, pathological subtype, and TNM staging to be independent prognostic factors.

Conclusions

We demonstrated that ASC were uncommon and aggressive lung tumors. Predominant histological subtype of AC might be an independent prognostic factor for ASC. Further prospective studies are warranted to clarify the characteristics of this rare tumor.

Predictive and prognostic value of preoperative serum tumor markers in resectable adenosqamous lung carcinoma

Background

Adenosquamous carcinoma is a rare and aggressive form of lung cancer. The prognostic and predictive value of preoperative serum tumor markers and frequency of EGFR mutations in adenosquamous lung carcinoma are unclear.

Methods

We retrospectively analyzed data and samples collected from 106 radically resected adenosquamous lung carcinoma patients with pathological stage I-IIIA between 2008 and 2013. Correlations between serum tumor marker levels and EGFR mutations as well as survival parameters were analyzed and prognostic factors were identified.

Results

Of the 106 adenosquamous lung carcinoma patients, 29 (27.4%) harbored EGFR mutations. By univariate analysis, advanced clinical stage (P = 0.009 for disease-free survival [DFS]; P = 0.046 for overall survival [OS]), larger tumor size (P = 0.001 for DFS; P = 0.002 for OS), regional lymph node metastasis (P = 0.024 for DFS; P = 0.030 for OS), higher NSE level (P = 0.002 for DFS; P < 0.001 for OS), and higher TMI (tumor marker index) (P = 0.009 for OS) were significantly correlated with a worse prognosis. By multivariate analysis, NSE (P = 0.014) was confirmed as independent predictor for DFS, while NSE (P = 0.001) and TMI (P = 0.038) were independent prognostic factors for OS.

Conclusion

Adenosquamous lung carcinoma is an aggressive malignancy with relatively high EGFR mutation frequency. Elevated preoperative NSE level and TMI are adverse predictive and prognostic indicators.

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.

Clinicopathological characteristics and survival outcomes in adenosquamous carcinoma of the lung: a population-based study from the SEER database

Adenosquamous carcinoma (ASC) of the lung is an unusual histology type in non-small-cell lung cancers. Due to its rarity, the clinicopathological characteristics and survival outcomes of the lung ASC are incompletely understood. We used the Surveillance, Epidemiology, and End Results (SEER) database to enroll 203,208 eligible patients, including 4,245 ASC, 124,253 adenocarcinoma (ADC) and 74,710 squamous cell carcinoma (SCC) patients. To date, this is the largest cohort in a study for ASC of the lung. With regard to age, sex, race, year of diagnosis, tumor size and SEER stage, ASC was intermediate between ADC and SCC. However, compared with ADC and SCC patients, ASC patients presented with a higher tumor grade and lower prevalence of nodal metastasis. More ASC patients underwent surgery and a lower proportion underwent radiation treatment and chemotherapy. Kaplan-Meier analysis showed that ASC patients had a better prognosis than ADC and SCC patients, but stratified analysis showed that the prognosis of ASC patients was worse than that of ADC and SCC patients in surgery and non-surgery subgroup. Multivariate analysis further confirmed that the ASC histology type was a risk factor for poor prognosis with respect to ADC and SCC. Using the propensity score matching to 1:1 match ASC with ADC or SCC, we found that ASC patients had worse survival than ADC and SCC patients. Subgroup analysis further demonstrated that ASC was a more aggressive histology type with a worse prognosis. These results provided a deep understanding of ASC, which contributed to better clinical diagnosis and treatment.

Clinical implications of the proliferative ability of the squamous component regarding tumor progression of adenosquamous carcinoma of the pancreas: A preliminary report

OBJECTIVES

The objectives of this study were to examine the clinicopathological characteristics of patients with adenosquamous carcinoma of the pancreas (ASCP) and assess whether the proliferative ability of the squamous cell carcinoma (SCC) component contributes to either its proportion within the tumor or tumor progression.

METHODS

We retrospectively reviewed 12 patients with resected ASCP and compared their clinicopathological characteristics with those of 161 patients with adenocarcinoma of the pancreas (ACP). The Ki-67 indexes of the separate ASCP components were assessed.

RESULTS

All the clinicopathological characteristics and outcomes were similar between the ASCP patients and ACP patients. Among the 12 ASCP cases, nine exhibited higher Ki-67 levels in the SCC component than in the corresponding adenocarcinoma (AC) component at primary sites (P = 0.022). The component with a higher Ki-67 level coincided with the predominant component at the primary site in nine of 11 patients. In all 10 patients who presented lymph node metastasis, the metastases almost entirely consisted of either the SCC or AC component. The SCC component was absent from metastatic lymph nodes in five of 10 patients even though the Ki-67 levels at the primary site in four of these patients were higher in the SCC component than in the AC component.

CONCLUSIONS

The enhanced proliferative ability of the SCC component of ASCP is reflected by its proportion within the tumor. However, other biological factors might contribute to metastasis in ASCP.

[Clinicopathologic Features and Prognostic Implications in 72 Cases with Lung Adenosquamous Carcinoma]

背景与目的

肺腺鳞癌是肺癌中的一种少见类型，混合有腺癌和鳞癌两种恶性组织成分，侵袭性高、预后差。本研究旨在探讨腺鳞癌的临床病理特点和预后影响因素。

方法

对72例肺腺鳞癌患者的临床病理资料进行回顾性分析，探讨影响患者预后的因素。

结果

全组患者中位生存期位34.7个月，5年生存率为14.9%，肿瘤长径、转移（metastasis, M）分期、肿瘤-淋巴结-转移（tumor-node-metastasis, TNM）病理分期、基因突变、手术对患者预后的影响有统计学意义。

结论

肺腺鳞癌恶性程度高、预后差，应采取手术为主的综合治疗，小分子酪氨酸激酶抑制剂治疗有助于延长患者生存期。

PD-L1 expression in lung adenosquamous carcinomas compared with the more common variants of non-small cell lung cancer

Lung adenosquamous cell carcinomas (ASCs) is a rare variant of NSCLC with a poorer prognosis and fewer treatment option than the more common variants. PD-L1 expression is reported to be the predictor of clinical response in trials of NSCLC. In our study, PD-L1 expression was evaluated via immunohistochemistry using a specific monoclonal antibody (SP263), and PD-L1 mRNA expression was evaluated via in situ hybridization. This study included 51 ASCs, 133 lung adenocarcinomas, and 83 lung squamous cell carcinomas (SCC). Similar results were obtained for PD-L1 expression measured at the mRNA and protein level (k coefficient, 0.851, P = 1.000). PD-L1 expression was significantly higher in the squamous versus glandular component of the 36 ASCs in which the components were analyzed separately. The PD-L1 expression rate was similar in the squamous cell component of ASCs and lung SCC (38.89% vs. 28.92%, P = 0.293), so does the adenocarcinoma component of ASCs and lung adenocarcinomas (11.11% vs 13.53%, P = 1.000). PD-L1 expression correlated significantly with lymphovascular invasion (P = 0.016), but not with EGFR, KRAS, and ALK mutations in lung ASCs. Anit-PD-L1 is a promising treatment option in lung ASC cases in which PD-L1 upregulated and EGFR mutations are present.

Evidence, Mechanism, and Clinical Relevance of the Transdifferentiation from Lung Adenocarcinoma to Squamous Cell Carcinoma

Lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) are two distinct subtypes of non-small-cell lung carcinoma. Interestingly, approximately 4% to 9% of human non-small-cell lung carcinoma tumors contain mixed adenomatous and squamous pathologies in a single lesion, clinically termed adenosquamous cell carcinoma. More important, these two different pathological components frequently share identical oncogenic mutations, indicative of a potential transition. Indeed, recent data have provided convincing evidence in supporting the ADC to SCC transdifferentiation in lungs. In the liver kinase B1 (official name STK11)-deficient mouse model, lung ADC can progressively transdifferentiate to SCC through pathologically mixed adenosquamous cell carcinoma as the intermediate status. Mechanistic studies further identify essential roles of extracellular matrix remodeling and metabolic reprogramming during this phenotypic transition. Small molecular compounds, including lysyl oxidase inhibitors and reactive oxygen species-inducing reagents such as phenformin, significantly accelerate the transition from lung ADC to SCC and thus confer lung tumors with drug resistance. Consistent with these findings, recent clinical studies have shown that epidermal growth factor receptor-mutant lung ADC can transdifferentiate to SCC in relapsed cancer patients. Together, these data support that this phenotypic transition from lung ADC to SCC might represent a novel mechanism for drug resistance. This review will summarize our current understanding of the transdifferentiation from lung ADC to SCC.

Genetic characterization drives personalized therapy for early-stage non-small-cell lung cancer (NSCLC) patients and survivors with metachronous second primary tumor (MST): A case report

RATIONALE

The pathogenesis and progression of lung cancer is a complicated process in which many genes take part. But molecular gene testing is typically only performed in advanced-stage non-squamous non-small-cell lung cancer (NSCLC). The value of tyrosine kinase inhibitors (TKI) administration is not widely recognized with respect to early-stage NSCLC.

PATIENT CONCERNS

Here, we present a case of a man, heavy smoker who initially presented with stage IA lung adenocarcinoma (LADC). Three years after a lung lobectomy, he was diagnosed with advanced lung squamous cell carcinoma (SCC), according to laboratory, imaging, and pathological examinations.

DIAGNOSES

The case initially had an early-stage LADC with an L858R epidermal growth factor receptor (EGFR) mutation. A subsequent advanced SCC bearing EGFR L858R/T790M mutations occurred 3 years after surgery.

INTERVENTIONS

The comprehensive therapy we utilized, including surgical resection for the early-stage lesion and GP chemotherapy and local radiotherapy as the first line therapy along with gefitinib maintenance treatment for the advanced metachronous second primary tumors (MST).

OUTCOMES

The synthetical therapy, have resulted in our patient with remaining alive and progression free for 4.5 years.

LESSONS

This case suggests that changes in molecular pathology should be monitored closely throughout cancer progression to guide personalized therapy and improve prognosis. We further review administration of TKI to early-stage NSCLC and to the metachronous second primary tumors (MST) in survivors.

Clinical outcomes of epidermal growth factor receptor tyrosine kinase inhibitors in recurrent adenosquamous carcinoma of the lung after resection

PURPOSE

The therapeutic efficacy of targeted therapy for adenosquamous carcinoma (ASC) of the lung remains unclear and the role of epidermal growth factor receptor (EGFR) testing in patients with ASC also remains controversial. We aimed to analyze the efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKIs) in ASC.

METHODS

Clinical records of patients with ASC who received treatment with EGFR-TKIs between January 2006 and December 2014 at two institutions were retrospectively reviewed.

RESULTS

A total of 27 EGFR mutation-positive patients with ASC who received TKI therapy were enrolled in this study. EGFR mutations included a deletion in exon 19 in 15 cases and a point mutation at codon 858 (L858R) in exon 21 in 12 cases. Among the 27 ASC patients who received treatment with EGFR-TKIs, nine had a partial response and 11 achieved stable disease, accounting for a disease control rate of 74.1% (20/27). The median postoperative overall survival (OS) of the EGFR-mutant patients who received TKI therapy was 39 months (95% confidence interval [CI]: 25.6-52.4). The median progression-free survival for EGFR mutation-positive patients was 15 months (95% CI: 12.9-17.1), and the median relapse OS was 19 months (95% CI: 0.9-37.1). In addition, the 3- and 5-year postoperative survival rate was 51.9% and 15.3%, respectively.

CONCLUSION

ASC patients harboring EGFR mutations had a good response to TKI therapy. Routine EGFR testing for ASCs was recommended. Further studies on TKI therapy versus chemotherapy alone for EGFR-mutant ASCs are required.

EGFR tyrosine kinase inhibitors versus chemotherapy as first-line therapy for non-small cell lung cancer patients with the L858R point mutation

The efficacy of EGFR tyrosine kinase inhibitors (TKIs) varies among different EGFR mutations. Here, we directly compared the efficacy of first-line TKIs to chemotherapy for non-small cell lung cancer (NSCLC) patients with the L858R mutation. The progression-free survival (PFS) for patients receiving TKIs as first-line therapy was longer than those who received chemotherapy (hazard ratio [HR]: 0.44, P < 0.001). Subgroup analyses showed that first-line TKI therapy resulted in longer PFS among non-smokers (HR: 0.41, P < 0.001), male (HR: 0.49, P = 0.002), female (HR: 0.39, P < 0.001), and patients with adenocarcinoma histology (HR: 0.41, P < 0.001). However, among patients with non-adenocarcinoma histology (HR: 1.11, P = 0.824) and those who used to smoke (HR: 0.55, P = 0.093), first-line TKI therapy failed to demonstrate statistically longer PFS compared to chemotherapy. Our results demonstrated that for patients with L858R mutation, first-line TKI therapy provided better survival benefits. However, among non-adenocarcinoma patients and those who used to smoke, the PFS in cohorts receiving first-line chemotherapy or TKI were not significantly different. The results of the current study will be helpful for decision-making in the treatment of patients with L858R mutation.

Evolution from genetics to phenotype: reinterpretation of NSCLC plasticity, heterogeneity, and drug resistance

Lung cancer is the leading cause of cancer-related deaths worldwide. Targeted therapy is beneficial in most cases, but the development of drug resistance stands as an obstacle to good prognosis. Multiple mechanisms were explored such as genetic alterations, activation of bypass signaling, and phenotypic transition. These intrinsic and/or extrinsic dynamic regulations facilitate tumor cell survival in meeting the demands of signaling under different stimulus. This review introduces lung cancer plasticity and heterogeneity and their correlation with drug resistance. While cancer plasticity and heterogeneity play an essential role in the development of drug resistance, the manipulation of them may bring some inspirations to cancer prognosis and treatment. That is to say, lung cancer plasticity and heterogeneity present us with not only challenges but also opportunities.

Molecular profiling of lung adenosquamous carcinoma: hybrid or genuine type?

Lung adenosquamous carcinoma is a particular subtype of non-small cell lung carcinoma that is defined by the coexistence of adenocarcinoma and squamous cell carcinoma components. The aim of this study was to assess the mutational profile in each component of 16 adenosquamous carcinoma samples from a Caucasian population by a combination of next generation sequencing using the cancer hotspot panel as well as the colon and lung cancer panel and FISH. Identified mutations were confirmed by Sanger sequencing of DNA from cancer cells of each component collected by Laser Capture microdissection. Mutations typical for adenocarcinoma as well as squamous cell carcinoma were identified. Driver mutations were predominantly in the trunk suggesting a monoclonal origin of adenosquamous carcinoma. Most remarkably, EGFR mutations and mutations in the PI3K signaling pathway, which accounted for 30% and 25% of tumors respectively, were more prevalent while KRAS mutations were less prevalent than expected for a Caucasian population. Surprisingly, expression of classifier miR-205 was intermediate between that of classical adenocarcinoma and squamous cell carcinoma suggesting that adenosquamous carcinoma is a transitional stage between these tumor types. The high prevalence of therapy-relevant targets opens new options of therapeutic intervention for adenosquamous carcinoma patients.

Improved survival associated with a balanced structure between adenomatous and squamous components in patients with adenosquamous carcinoma of the lung

BACKGROUND

Primary adenosquamous carcinoma (ASC) of the lung is rare and its biological behavior has not yet been thoroughly described. The aim of this study was to analyze the clinicopathological characteristics and prognostic factors associated with ASC.

MATERIALS

Clinical records of patients with ASC of the lung who underwent surgery between October 2008 and December 2014 in a single institution were retrospectively reviewed.

RESULTS

A total of 205 patients were identified. Patients with balanced structural components had significantly better prognosis than those with squamous (p = 0.014) or adenomatous (p < 0.001) predominance, and those with N0, N1, and N2 ASC (N0 vs. N1 [ p = 0.031] and N1 vs. N2 [p = 0.037], respectively), or stage I, II and IIIA ASC (stage I vs. II [p = 0.021] and stage II vs. IIIA [p = 0.007], respectively) had significant differences with respect to overall survival (OS). Multivariate analysis identified structural components (p = 0.011), tumor, node and metastasis (TNM) status (p < 0.001), and adjuvant chemotherapy (p = 0.008) as significantly prognostic factors for OS, and structural components (p = 0.030), TNM stage (p < 0.001) and adjuvant chemotherapy (p = 0.005) as the corresponding variables for disease-free survival.

CONCLUSIONS

A balanced structure between adenomatous and squamous components in patients with primary ASC of the lung was associated with better prognosis.

Epidermal Growth Factor Receptor Activating Mutations in Squamous Histology of Lung Cancer Patients of Southern Bulgaria

There is only limited data on the prevalence of epidermal growth factor receptor (EGFR) activating mutations in squamous cell carcinomas and adenosquamous carcinomas of the lung in patients of the Southern Bulgarian region and the efficacy of EGFR tyrosine kinase inhibitors. AIM: Previous reports for Bulgarian population showed high incidence of EGFR mutations in the squamous cell carcinomas, so we set the goal to investigate their frequency in Southern Bulgaria, after precise immunohistochemical verification of lung cancers. MATERIALS AND METHODS: Two hundred and thirty-six lung carcinomas were included in this prospective study. All biopsies were initially analysed with p63, TTF1, Napsin A, CK7, CK34βE12, synaptophysin, CK20 and CDX2. Two hundred and twenty-five non-small cell lung carcinomas were studied with real-time PCR technology to assess the status of the EGFR gene. RESULTS: We detected 132 adenocarcinomas (58.7%), 89 squamous cell carcinomas (39.2%), 4 adenosquamous carcinomas (1.8%), 9 large cell neuroendocrine carcinomas (3.8%) and 2 metastatic colorectal adenocarcinomas (0.8%). Activating mutations in the EGF receptor had 3 out of 89 squamous cell carcinomas (3.37%). We have established mutations in L858R, deletion in exon 19 and rare mutation in S7681. One out of four adenosquamous carcinomas had a point mutation in the L858R (25%). CONCLUSIONS: The frequency of EGFR mutations we found in lung squamous cell carcinomas in a Southern Bulgarian region is lower than that in European countries. Ethnic diversity in the region does not play role of an independent predictive factor in terms of mutation frequency.

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.

Screening for major driver oncogene alterations in adenosquamous lung carcinoma using PCR coupled with next-generation and Sanger sequencing methods

We investigated the frequency of major driver oncogenes in lung adenosquamous cell carcinoma (ASC) cases. Frequency of EGFR, K-Ras, B-Raf, PIK3CA, DDR2, ALK, and PDGFRA gene mutations was examined in 56 patients using next-generation sequencing, polymerase chain reaction, and Sanger sequencing. Macrodissection or microdissection was performed in 37 cases to separate the adenomatous and squamous components of ASC. The overall mutation rate was 64.29%, including 55.36%, 7.14%, and 1.79% for EGFR, K-Ras, and B-Raf mutations, respectively. PIK3CA mutation was detected in three cases; all involved coexisting EGFR mutations. Of the 37 cases, 34 were convergent in two components, while three showed EGFR mutations in the glandular components and three showed PIK3CA mutations in the squamous components. With respect to EGFR mutations, the number of young female patients, nonsmokers, and those with positive pleural invasion was higher in the mutation-positive group than that in the mutation-negative. K-Ras mutation was significantly associated with smoking. Overall survival in the different EGFR mutation groups differed significantly. The frequency and clinicopathological characteristics of EGFR- and K-Ras-mutated adenosquamous lung carcinoma were similar to that noted in Asian adenocarcinomas patients. The high convergence mutation rate in both adenomatous and squamous components suggests monoclonality in ASC.

Transdifferentiation of lung adenocarcinoma in mice with Lkb1 deficiency to squamous cell carcinoma

Lineage transition in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) of non-small cell lung cancer, as implicated by clinical observation of mixed ADC and SCC pathologies in adenosquamous cell carcinoma, remains a fundamental yet unsolved question. Here we provide in vivo evidence showing the transdifferentiation of lung cancer from ADC to SCC in mice: Lkb1-deficient lung ADC progressively transdifferentiates into SCC, via a pathologically mixed mAd-SCC intermediate. We find that reduction of lysyl oxidase (Lox) in Lkb1-deficient lung ADC decreases collagen disposition and triggers extracellular matrix remodelling and upregulates p63 expression, a SCC lineage survival oncogene. Pharmacological Lox inhibition promotes the transdifferentiation, whereas ectopic Lox expression significantly inhibits this process. Notably, ADC and SCC show differential responses to Lox inhibition. Collectively, our findings demonstrate the de novo transdifferentiation of lung ADC to SCC in mice and provide mechanistic insight that may have important implications for lung cancer treatment.

Intratumor Heterogeneity of ALK-Rearrangements and Homogeneity of EGFR-Mutations in Mixed Lung Adenocarcinoma

BACKGROUND

Non Small Cell Lung Cancer is a highly heterogeneous tumor. Histologic intratumor heterogeneity could be 'major', characterized by a single tumor showing two different histologic types, and 'minor', due to at least 2 different growth patterns in the same tumor. Therefore, a morphological heterogeneity could reflect an intratumor molecular heterogeneity. To date, few data are reported in literature about molecular features of the mixed adenocarcinoma. The aim of our study was to assess EGFR-mutations and ALK-rearrangements in different intratumor subtypes and/or growth patterns in a series of mixed adenocarcinomas and adenosquamous carcinomas.

METHODS

590 Non Small Cell Lung Carcinomas tumor samples were revised in order to select mixed adenocarcinomas with available tumor components. Finally, only 105 mixed adenocarcinomas and 17 adenosquamous carcinomas were included in the study for further analyses. Two TMAs were built selecting the different intratumor histotypes. ALK-rearrangements were detected through FISH and IHC, and EGFR-mutations were detected through IHC and confirmed by RT-PCR.

RESULTS

10/122 cases were ALK-rearranged and 7 from those 10 showing an intratumor heterogeneity of the rearrangements. 12/122 cases were EGFR-mutated, uniformly expressing the EGFR-mutated protein in all histologic components.

CONCLUSION

Our data suggests that EGFR-mutations is generally homogeneously expressed. On the contrary, ALK-rearrangement showed an intratumor heterogeneity in both mixed adenocarcinomas and adenosquamous carcinomas. The intratumor heterogeneity of ALK-rearrangements could lead to a possible impact on the therapeutic responses and the disease outcomes.

Metastatic Squamous Cell Carcinoma Component from an Adenosquamous Carcinoma of the Lung with Identical Epidermal Growth Factor Receptor Mutations

The case reported is a young “light” ex-smoker who initially had a localized adenosquamous carcinoma bearing an epidermal growth factor receptor (EGFR) sensitizing mutation. He first recurred six months after initial treatment within the brain with a pure squamous histology and the same EGFR mutation. Surgical resection and radiation rendered him disease-free. Subsequent isolated recurrence within the lung eighteen months later was a pure adenocarcinoma, again with the same identified EGFR mutation. These histologic changes (from adenosquamous to pure squamous to pure adenocarcinoma) have been described but not before in the absence of any selection pressure with EGFR tyrosine kinase inhibitors. This case points out the histologic “flexibility” of EGFR mutant lung cancers and the importance for appropriate molecular testing in nonsmokers with lung cancer of any histologic type.