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

Molecular mechanisms and therapeutic strategies for small‑cell lung cancer transformation after TKI therapy in EGFR‑mutated lung adenocarcinoma (Review)

Lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutations is a common subtype of non-small cell lung cancer (NSCLC). Although it responds well to EGFR-tyrosine kinase inhibitors (EGFR-TKIs), acquired resistance to EGFR-TKIs inevitably occurs, which limits the use of the EGFR-TKIs. One resistance mechanism is small-cell transformation, which refers to the histological switch of EGFR-mutant lung adenocarcinoma to a small-cell lung cancer phenotype following TKI exposure. Small cell transformation is associated with a poor prognosis and requires different treatment modalities compared with NSCLC. The molecular mechanisms underlying small cell transformation are not fully elucidated, but may involve the loss of tumor suppressor genes, such as RB1 and TP53, and the activation of neuroendocrine pathways. In the present review, the current advances in the molecular characteristics and therapeutic regimens for small-cell transformation in patients with EGFR-mutated lung adenocarcinoma who are resistant to EGFR-TKIs, are summarized.

Comparison Between Endobronchial-Guided Transbronchial Biopsy and Computed Tomography-Guided Transthoracic Lung Biopsy for the Diagnosis of Central Pulmonary Lesions

BACKGROUND

Lung cancer is one of the most common malignant tumors at present. This study aimed to compare the diagnostic accuracy, complication rates, and predictive values of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) and electronic bronchoscopy-guided transbronchial lung biopsy (TBLB) for patients with central pulmonary lesions (CPLs) with a diameter ≥ 3 cm.

METHODS

We retrospectively included 110 patients with CPLs with a diameter ≥ 3 cm who underwent preoperative PTNB and TBLB examinations and ultimately underwent surgery to remove CPLs and obtained pathological results. Detailed information was collected in order to compare whether there was a difference between two groups. Data were processed using SPSS software (Version 26.0; IBM Corp). Data were compared by t-test or chi-square test. p < 0.05 was considered statistically significant.

RESULTS

All patients underwent surgical treatment at the department of thoracic surgery and obtained a final pathological diagnosis. The rate of positive predictive value (PPV) was comparable between the two methods, and the negative predictive value (NPV) was significantly higher in the PTNB group compared with the TBLB group (p < 0.05). In addition, PTNB was more sensitive and accurate than TBLB (p < 0.05). However, the PTNB group had a higher probability of complications, and TBLB was a relatively safer examination method.

CONCLUSION

PTNB demonstrated a higher accuracy and sensitivity than TBLB in the treatment of CPLs with a diameter ≥ 3 cm, but the complication rates of PTNB are relatively high. These methods exhibited different diagnostic accuracies and therefore should be selected based on different medical conditions.

Exploring the prognostic impact of differences in treatment strategies for SCLC with different histologies and prognostic factors for C-SCLC: A SEER population-based study

Background

Combined small cell lung cancer (C-SCLC) is a rare type of small cell lung cancer (SCLC), and it is controversial whether to choose the same treatment regimen as SCLC due to its multiple histologic components.

Study methods and results

Records of patients with small cell lung cancer diagnosed between 2010 and 2020 were extracted using the SEER database. The OS of patients with different histological types under the same staging and treatment regimen was analyzed. It was found that early-stage (stage IA-IIA) surgical treatment, systemic chemotherapy alone, and chemoradiotherapy were more efficacious than C-SCLC and P-SCLC in patients with limited-stage (P = 0.054, P = 0.001, P = 0.019). In patients with extensive staging, the OS of patients with systemic chemotherapy regimens differed (P = 0.045) and was better in C-SCLC than in P-SCLC. We further explored the treatment strategy for patients with C-SCLC, which was shown by a COX regression model based on prognostic factors screened by Random Forest and LASSO regression models. Surgery, radiotherapy, and chemotherapy would be beneficial for survival. In a subgroup analysis based on stage and treatment regimen, it was shown that patients with early staging (stage IA-IIA) had a better prognosis with surgery (P < 0.001); in patients with extensive staging, chemoradiotherapy was favorable to the patient's prognosis (P = 0.022).

Conclusion

Both limited-stage and extensive-stage C-SCLC patients are more sensitive to chemotherapy than P-SCLC patients. Patients with C-SCLC who have access to surgery should undergo surgery as early as possible, while chemoradiotherapy is recommended for patients with extensive staging. Patient age, gender, tumor size, surgery, chemotherapy, radiotherapy, and metastasis may individually affect patient prognosis.

EHMT2-mediated transcriptional reprogramming drives neuroendocrine transformation in non-small cell lung cancer

The transformation of lung adenocarcinoma to small cell lung cancer (SCLC) is a recognized resistance mechanism and a hindrance to therapies using epidermal growth factor receptor tyrosine kinase inhibitors (TKIs). The paucity of pretranslational/posttranslational clinical samples limits the deeper understanding of resistance mechanisms and the exploration of effective therapeutic strategies. Here, we developed preclinical neuroendocrine (NE) transformation models. Next, we identified a transcriptional reprogramming mechanism that drives resistance to erlotinib in NE transformation cell lines and cell-derived xenograft mice. We observed the enhanced expression of genes involved in the EHMT2 and WNT/β-catenin pathways. In addition, we demonstrated that EHMT2 increases methylation of the SFRP1 promoter region to reduce SFRP1 expression, followed by activation of the WNT/β-catenin pathway and TKI-mediated NE transformation. Notably, the similar expression alterations of EHMT2 and SFRP1 were observed in transformed SCLC samples obtained from clinical patients. Importantly, suppression of EHMT2 with selective inhibitors restored the sensitivity of NE transformation cell lines to erlotinib and delayed resistance in cell-derived xenograft mice. We identify a transcriptional reprogramming process in NE transformation and provide a potential therapeutic target for overcoming resistance to erlotinib.

Small cell lung cancer transformations from non-small cell lung cancer: Biological mechanism and clinical relevance

Lung cancer is a leading cause of cancer deaths worldwide, consisting of two major histological subtypes: small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). In some cases, NSCLC patients may undergo a histological transformation to SCLC during clinical treatments, which is associated with resistance to targeted therapy, immunotherapy, or chemotherapy. The review provides a comprehensive analysis of SCLC transformation from NSCLC, including biological mechanism, clinical relevance, and potential treatment options after transformation, which may give a better understanding of SCLC transformation and provide support for further research to define better therapy options.

Enhancing the prediction of the invasiveness of pulmonary adenocarcinomas presenting as pure ground-glass nodules: Integrating intratumor heterogeneity score with clinical-radiological features via machine learning in a multicenter study

Objective

The invasiveness of lung adenocarcinoma significantly impacts clinical decision-making. However, assessing this invasiveness preoperatively, especially when it manifests as pure ground-glass nodules (pGGN) on CT scans, poses challenges. This study aims to quantify intratumor heterogeneity (ITH) and determine whether the ITH score can enhance the accuracy of invasiveness predictions.

Methods

A total of 524 patients with lung adenocarcinomas presenting as pGGN were enrolled in the study, with 177 (33.78%) receiving a pathologic diagnosis of invasiveness. Four diagnostic approaches were developed to predict the invasiveness of lung adenocarcinoma presenting as pGGN: (1) conventional lesion size, (2) ITH score, (3) clinical-radiological features (ClinRad), and (4) integration of the ITH score with ClinRad. ClinRad alone or in combination with the ITH score served as the input for 11 machine learning approaches. The trained models were evaluated in an independent validation cohort, and the area under the curve (AUC) was calculated to assess classification performance.

Results

The conventional lesion size showed the lowest performance, with an AUC of 0.826 (95% confidence interval [CI]: 0.758-0.894), while the ITH score outperformed it with an AUC of 0.846 (95% CI: 0.787-0.905). The CatBoost model performed best when the ITH score and ClinRad were both used as input features, leading to the development of an ITH-ClinRad-guided CatBoost classifier. CatBoost also excelled with ClinRad alone, resulting in a ClinRad-guided CatBoost classifier with an AUC of 0.830 (95% CI: 0.764-0.896), surpassed by the ITH-ClinRad-guided CatBoost classifier with an AUC of 0.871 (95% CI: 0.818-0.924).

Conclusion

The ITH-ClinRad-guided CatBoost classifier emerges as a promising tool with significant potential to revolutionize the management of lung adenocarcinomas presenting as pGGNs.

Efficacy of Tyrosine Kinase Inhibitors in Primary Driver-Gene-Positive Combined Small-Cell Lung Cancer: A Retrospective Study

BACKGROUND

Combined small-cell lung cancer (c-SCLC) with gene mutations is a rare subtype often found alongside adenocarcinoma. Targeted therapy may be effective because of the presence of specific molecular targets. However, due to its rarity and unconventional genetic testing, the efficacy remains uncertain.

METHODS

A total of 31 c-SCLC patients with gene mutations were retrospectively included and grouped according to their treatment regimens. Treatment outcomes were evaluated. Kaplan-Meier method was used for survival analysis, with Log Rank test applied for comparison between groups.

RESULTS

We divided the 31 patients into 3 groups according to first-line treatment: group A (chemotherapy, n = 16), group B (targeted monotherapy, n = 7), and group C (targeted combination therapy, n = 8). The overall response rates (ORR) were 43.8%, 42.9%, and 62.5%. The disease control rates (DCR) were 87.5%, 85.7%, and 100%. The median progression-free survival (PFS) was 4.0, 5.0, and 7.93 months (P = .024), with a significant difference between group A and C (P = .010). The median overall survival (OS) was 14.10, 17.43, and 12.93 months (P = .313). Seven patients in group A received targeted therapy in later-line. Of the total 22 patients received targeted monotherapy or combination therapy, the ORR and DCR were 54.5% and 90.9%. The median PFS and OS were 5.87 and 17.30 months. Additionally, adverse events (AEs) occurred in 53.8% and 88.9% of monotherapy and combination therapy. The most common AEs in monotherapy were elevated transaminases (23.1%) and in combination anemia (66.7%).

CONCLUSIONS

TKIs showed encouraging efficacy in driver-gene-positive c-SCLC. While monotherapy may be a supplementary option, combination with chemotherapy appears to be preferable and superior.

Exploring the molecular features and genetic prognostic factors of pulmonary high-grade neuroendocrine carcinomas

Molecular research on large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC) has progressed significantly. However, there are still fewer molecular markers related to prognostic/therapeutic strategies for these conditions compared to those for adenocarcinoma. We therefore investigated the molecular characteristics of neuroendocrine carcinomas (NECs). We enrolled patients surgically diagnosed with NECs between 2011 and 2019, with complete follow-up records. All were analyzed using whole exome sequencing and p53/Rb immunohistochemistry (IHC). A total of 92 cases, comprising 45 pure SCLC, 15 combined SCLC, 27 pure LCNEC, and 5 combined LCNEC, were included. TP53 (78.3%) and RB1 (34.8%) were the most common molecular alterations, followed by KMT2D, LRP1B, FAT3, NCOR2, SPTA1, and NOTCH1. The mutation frequency for EGFR was 10.9%. Sixteen patients with LCNEC who had TP53/RB1 co-alterations were SCLC-like, while the remaining were NSCLC-like. There was no statistically significant difference between the groups regarding overall survival (OS; p = 0.458) and progression-free survival (PFS; p = 0.157). The frequency of the loss of Rb expression by IHC in SCLC-like LCNEC was 100%. Significant pathway alterations unique to SCLC included Notch and AMPK, while HIF-1 was enriched exclusively in LCNEC. NCOR2 mutation was linked to worse OS (p = 0.029) and PFS (p = 0.015), while wild-type SPTA1 was associated with poor PFS (p = 0.018). IHC for Rb was reliable for predicting LCNEC molecular subtypes, indicating its clinical value. NCOR2 and SPTA1 alterations were identified as prognostic factors that may provide therapeutic targets for patients with NEC.

Salvage Surgery for Advanced Lung Adenocarcinoma After Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Treatment

BACKGROUND

No published studies to date have evaluated the detailed pathologic and genetic features of lung adenocarcinoma after epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy and salvage surgery. We aimed to evaluate the pathologic and genetic changes of tumors in patients with advanced lung adenocarcinoma treated with EGFR TKI therapy and salvage surgery.

METHODS

This study retrospectively collected data from 29 advanced lung adenocarcinoma patients who underwent EGFR TKI therapy, followed by salvage operation, between January 2010 and December 2018. All patients had partial response or stable disease without evidence of progressive disease. Next-generation sequencing was used to determine whether acquired resistant mutations in morphologically treatment-sensitive and morphologically treatment-resistant regions of tumor existed.

RESULTS

There were 3, 22, and 4 patients with clinical stage IIIB, IVA, and IVB, respectively. After a mean TKI treatment duration of 134 days, 27 patients had partial response, 2 had stable disease, and 27.6% of patients were downstaged before salvage surgery. All patients had residual viable tumor cells in their tumor bed; 5 patients (17.2%) had a major pathologic response. Acquired T790M mutations (n = 4), histologic transformations (n = 2), and acquired T790M mutation with histologic transformation (n = 1) were identified in the morphologically treatment-resistant regions of tumors. The 3-year overall survival was 75.9%.

CONCLUSIONS

The presence of morphologically treatment-resistant tumor regions with acquired T790M mutations and histologic transformations demonstrate the existence of resistant subclones in TKI-treated tumors before disease progression. Salvage surgery performed in selected patients before disease progression may improve survival by removing TKI-resistant subclones.

Can Liquid Biopsy Based on ctDNA/cfDNA Replace Tissue Biopsy for the Precision Treatment of EGFR-Mutated NSCLC?

More and more clinical trials have explored the role of liquid biopsy in the diagnosis and treatment of EGFR-mutated NSCLC. In certain circumstances, liquid biopsy has unique advantages and offers a new way to detect therapeutic targets, analyze drug resistance mechanisms in advanced patients, and monitor MRD in patients with operable NSCLC. Although its potential cannot be ignored, more evidence is needed to support the transition from the research stage to clinical application. We reviewed the latest progress in research on the efficacy and resistance mechanisms of targeted therapy for advanced NSCLC patients with plasma ctDNA EGFR mutation and the evaluation of MRD based on ctDNA detection in perioperative and follow-up monitoring.

Progress in the knowledge on the transformation of lung adenocarcinoma to small-cell lung cancer

Lung cancer is a common type of carcinoma and is the leading cause of cancer-related deaths worldwide. The two broad histological subtypes of lung cancer are non-small-cell lung cancer (NSCLC), which accounts for 85% of cases and includes adenocarcinoma and squamous cell carcinoma, and small-cell lung cancer (SCLC), which accounts for 15% of cases. Substantial improvements in treatment have led to remarkable progress and changed outcomes for many patients in the past two decades. However, with prolonged survival time and awareness of repeat biopsy, more and more patients with lung cancer have been found to undergo a histological transformation during treatment, with lung adenocarcinoma (LAdC) to SCLC transformation being the most frequent. In this article, we summarized findings on the mechanism, clinical characteristics, therapeutic strategies, and predictors of the transformation of LAdC to SCLC. A non-systematic narrative review was performed using the Pubmed/MEDLINE (US National Library of Medicine National Institutes of Health) database with the following keywords: "transformation from NSCLC to SCLC," "transformation from lung adenocarcinoma to small-cell lung cancer," "NSCLC transformation in SCLC," and "NSCLC and transformation and SCLC." Articles published until June 2022 were analyzed. Search results were limited to human studies without restriction for language.

Clinicopathological Features and Significance of Epidermal Growth Factor Receptor Mutation in Surgically Resected Early-Stage Lung Adenocarcinoma

The clinicopathological presentation of early-stage lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutations has been seldom studied. Our study enrolled patients with stage I and II lung adenocarcinoma between January 2014 and December 2017 at the National Taiwan University Hospital. Clinicopathological features and prognosis were retrospectively reviewed and analyzed depending on EGFR mutation status. EGFR mutations were detected in 622 (60%) out of 1034 patients. Compared to the group without EGFR mutations, the group with EGFR mutations had more patients above 65 years of age (p < 0.001), more non-lepidic histological subtypes (p < 0.001), higher CEA levels (p = 0.044), higher grade of pleural (p = 0.02) and lymphovascular (p = 0.001) invasion, higher histological grade (p < 0.001), and a more advanced pathological stage (p = 0.022). In multivariate analysis, there was no significant difference in PFS or OS between the EGFR mutant and wild-type groups. In subtype analysis, the tumors with an L858R mutation had a more lepidic predominant histological type (p = 0.019) and less lymphovascular invasion (p = 0.011). No significant differences in PFS or OS were detected between the exon 19 deletion and L858R mutation groups. In early-stage lung adenocarcinoma, EGFR mutation may be considered as a treatment response predictor for tyrosine kinase inhibitors, instead of a predictor of clinical prognosis.

Small-Cell Lung Cancer Transformation as a Mechanism of Resistance to Pralsetinib in RET-Rearranged Lung Adenocarcinoma: A Case Report

The majority of resistance to Rearranged during transfection (RET)-specific tyrosine kinase inhibitors (TKI) described in RET-rearranged non-small cell lung cancer (NSCLC) patients are driven by RET-independent mechanisms. We provide the first case report of a RET-rearranged lung adenocarcinoma (LUAD) transformation into small-cell lung cancer (SCLC) as a mechanism of acquired resistance to pralsetinib. A 43-year-old patient presented with a RET-rearranged LUAD revealed by pleural effusion. After 14 months of response to pralsetinib, biopsy of a progressive pleural lesion found a phenotypic transformation into SCLC. Molecular analysis identified the same RET fusion and TP53 mutation in both primary adenocarcinoma and recurrence as SCLC. The patient achieved partial response after switch to carboplatin and etoposide chemotherapy and presented with progression disease after 6 months. Histological transformation could be a mechanism of resistance to RET-TKIs and rebiopsy should be considered to adapt subsequent treatment.

PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism: Potential targets to overcome radioresistance in small cell lung cancer

Small cell lung cancer (SCLC) is a highly aggressive tumor type for which limited therapeutic progress has been made. Platinum-based chemotherapy with or without thoracic radiotherapy remains the backbone of treatment, but most patients with SCLC acquire therapeutic resistance. Given the need for more effective therapies, better elucidation of the molecular pathogenesis of SCLC is imperative. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is frequently activated in SCLC and strongly associated with resistance to ionizing radiation in many solid tumors. This pathway is an important regulator of cancer cell glucose metabolism, and its activation probably effects radioresistance by influencing bioenergetic processes in SCLC. Glucose metabolism has three main branches-aerobic glycolysis, oxidative phosphorylation, and the pentose phosphate pathway-involved in radioresistance. The interaction between the PI3K/AKT/mTOR pathway and glucose metabolism is largely mediated by hypoxia-inducible factor 1 (HIF-1) signaling. The PI3K/AKT/mTOR pathway also influences glucose metabolism through other mechanisms to participate in radioresistance, including inhibiting the ubiquitination of rate-limiting enzymes of the pentose phosphate pathway. This review summarizes our understanding of links among the PI3K/AKT/mTOR pathway, hypoxia, and glucose metabolism in SCLC radioresistance and highlights promising research directions to promote cancer cell death and improve the clinical outcome of patients with this devastating disease.

Crosstalk between PI3K/Akt and Wnt/β-catenin pathways promote colorectal cancer progression regardless of mutational status

The PI3K/Akt and Wnt/β-catenin pathways play an important role in the acquisition of the malignant phenotype in cancer. However, there are few data regarding the role of the interplay between both pathways in colorectal cancer (CRC) progression. The mutational status and the clinicopathological characteristics of PI3K/Akt and Wnt/β-catenin pathways were accessed by bioinformatic analysis whereas that the impact of the interplay between the activity of both pathways to explain tumorigenic potential was performed in vitro using IGF-1 and Wnt3a treatments in CRC cell models. The mutational status of these pathways did not influence the survival of CRC patients, but an association between clinicopathological characteristics in patients with mutations in one, but not in both pathways was observed. A potentiating effect on the activation of both pathways and enhanced cellular migration and proliferation was observed when both pathways were activated simultaneously with IGF-1 and Wnt3a. In addition, these effects were hindered after pretreatment with LY294002, a specific PI3K inhibitor, suggesting some dependence between these two signaling cascades. Our findings show that, regardless of mutational status, there is an interplay between the activity of PI3K/Akt and Wnt/β-catenin pathways that contributes to events related to CRC progression and that the reversal of such events using a PI3K inhibitor highlights the value of targeting these pathways for potential directed therapies in CRC patients.

CT-Based Radiomic Analysis for Preoperative Prediction of Tumor Invasiveness in Lung Adenocarcinoma Presenting as Pure Ground-Glass Nodule

It remains a challenge to preoperatively forecast whether lung pure ground-glass nodules (pGGNs) have invasive components. We aimed to construct a radiomic model using tumor characteristics to predict the histologic subtype associated with pGGNs. We retrospectively reviewed clinicopathologic features of pGGNs resected in 338 patients with lung adenocarcinoma between 2011-2016 at a single institution. A radiomic prediction model based on forward sequential selection and logistic regression was constructed to differentiate adenocarcinoma in situ (AIS)/minimally invasive adenocarcinoma (MIA) from invasive adenocarcinoma. The study cohort included 133 (39.4%), 128 (37.9%), and 77 (22.8%) patients with AIS, MIA, and invasive adenocarcinoma (acinar 55.8%, lepidic 33.8%, papillary 10.4%), respectively. The majority (83.7%) underwent sublobar resection. There were no nodal metastases or tumor recurrence during a mean follow-up period of 78 months. Three radiomic features-cluster shade, homogeneity, and run-length variance-were identified as predictors of histologic subtype and were selected to construct a prediction model to classify the AIS/MIA and invasive adenocarcinoma groups. The model achieved accuracy, sensitivity, specificity, and AUC of 70.6%, 75.0%, 70.0%, and 0.7676, respectively. Applying the developed radiomic feature model to predict the histologic subtypes of pGGNs observed on CT scans can help clinically in the treatment selection process.

Sequential small cell transformation and T790M mutation in an epidermal growth factor-mutant lung adenocarcinoma: A rare occurrence with significant management implications

BACKGROUND

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) resistance may be acquired via genotypic and/or phenotypic transformations. Herein, we report an extremely uncommon case with sequential small cell transformation and EGFR T790M mutation, in an elderly female with EGFR exon 21 L858R-mutant lung adenocarcinoma, following treatment with a first-generation EGFR-TKI.

CASE

A 67-year-old female never-smoker presented with a cough and dyspnoea of 2 months' duration. Computerised tomography revealed a 39 mm lesion in the upper lobe of the right lung with pleural effusion. Pleural fluid cytology revealed metastatic lung adenocarcinoma, and EGFR testing revealed exon 21 L858R mutation. She was started on gefitinib. After a progression-free survival of 31 months, she presented with disease progression and multiple extra-thoracic metastases. Fine needle aspiration cytology of a chest wall lesion revealed metastatic small cell carcinoma. EGFR testing on this aspirate revealed persistent L858R mutation only. In view of small cell transformation, chemotherapy (etoposide and carboplatin) was administered. After 4 months, ascitic fluid cytology revealed metastatic adenocarcinoma with persistent L858R mutation and an acquired T790M mutation (both detected on liquid biopsy as well) indicating amplification of the adenocarcinoma clone and regression of the small cell carcinoma clone. She was then initiated on osimertinib.

CONCLUSIONS

The index case highlights the significance of serial EGFR genotyping along with repeated tissue and/or blood sampling in the prompt detection of genetic and phenotypic resistance mechanisms to EGFR-TKIs. Furthermore, it lends evidence in support of the upfront treatment approaches targeting the heterogeneity of acquired EGFR-TKI resistance mechanisms.

Comprehensive genetic analysis of histological components of combined small cell carcinoma

Background

Combined small‐cell lung cancer (cSCLC) is a rare type of small‐cell lung cancer (SCLC) that includes both SCLC and non‐small‐cell lung cancer (NSCLC). The molecular biological mechanisms underlying the heterogeneity of histological types in combined or metachronously transformed SCLC (mtSCLC) remain unclear. This study aimed to investigate the relationship between genetic alterations and each histological component heterogeneously detected in cSCLC and mtSCLC.

Methods

This study included four cSCLC cases and one mtSCLC case. Formalin‐fixed and paraffin‐embedded sections of each histological component of these tumors were subjected to next‐generation sequencing (NGS) and quantitative reverse transcription‐polymerase chain reaction to investigate the genetic mutations and expression levels of neuroendocrine cell‐specific transcription factors (achaete‐scute homolog‐1 [ASCL1], brain‐2 [BRN2] also known as POU domain class 3 transcription factor 2, nuclear factor 1 B [NF1B], insulinoma‐associated protein 1 [INSM1], and thyroid transcription factor‐1 [TTF‐1]).

Results

NGS analysis revealed that SCLC and NSCLC components share the same somatic mutations detected most frequently in TP53, and also in RB1 and EGFR. Gene expression analysis showed ASCL1 expression was significantly lower in the NSCLC component than in the SCLC component.

Conclusion

We conclude that the morphological evolution of heterogeneous histological components in cSCLC may be associated with differences in ASCL1 expression levels, but not in acquired somatic gene mutations.

State-of-the-Art Molecular Oncology of Lung Cancer in Taiwan

Lung cancers are life-threatening malignancies that cause great healthcare burdens in Taiwan and worldwide. The 5-year survival rate for Taiwanese patients with lung cancer is approximately 29%, an unsatisfactorily low number that remains to be improved. We first reviewed the molecular epidemiology derived from a deep proteogenomic resource in Taiwan. The nuclear factor erythroid 2-related factor 2 (NRF2)antioxidant mechanism was discovered to mediate the oncogenesis and tumor progression of lung adenocarcinoma. Additionally, DNA replication, glycolysis and stress response are positively associated with tumor stages, while cell-to-cell communication, signaling, integrin, G protein coupled receptors, ion channels and adaptive immunity are negatively associated with tumor stages. Three patient subgroups were discovered based on the clustering analysis of protein abundance in tumors. The first subgroup is associated with more advanced cancer stages and visceral pleural invasion, as well as higher mutation burdens. The second subgroup is associated with EGFR L858R mutations. The third subgroup is associated with PI3K/AKT pathways and cell cycles. Both EGFR and PI3K/AKT signaling pathways have been shown to induce NRF2 activation and tumor cell proliferation. We also reviewed the clinical evidence of patient outcomes in Taiwan given various approved targeted therapies, such as EGFR-tyrosine kinase inhibitors and anaplastic lymphoma kinase (ALK)inhibitors, in accordance with the patients’ characteristics. Somatic mutations occurred in EGFR, KRAS, HER2 and BRAF genes, and these mutations have been detected in 55.7%, 5.2%, 2.0% and 0.7% patients, respectively. The EGFR mutation is the most prevalent targetable mutation in Taiwan. EML4-ALK translocations have been found in 9.8% of patients with wild-type EGFR. The molecular profiling of advanced NSCLC is critical to optimal therapeutic decision-making. The patient characteristics, such as mutation profiles, protein expression profiles, drug-resistance profiles, molecular oncogenic mechanisms and patient subgroup systems together offer new strategies for personalized treatments and patient care.

Automated 3D Segmentation of the Aorta and Pulmonary Artery on Non-Contrast-Enhanced Chest Computed Tomography Images in Lung Cancer Patients

Pulmonary hypertension should be preoperatively evaluated for optimal surgical planning to reduce surgical risk in lung cancer patients. Preoperative measurement of vascular diameter in computed tomography (CT) images is a noninvasive prediction method for pulmonary hypertension. However, the current estimation method, 2D manual arterial diameter measurement, may yield inaccurate results owing to low tissue contrast in non-contrast-enhanced CT (NECT). Furthermore, it provides an incomplete evaluation by measuring only the diameter of the arteries rather than the volume. To provide a more complete and accurate estimation, this study proposed a novel two-stage deep learning (DL) model for 3D aortic and pulmonary artery segmentation in NECT. In the first stage, a DL model was constructed to enhance the contrast of NECT; in the second stage, two DL models then applied the enhanced images for aorta and pulmonary artery segmentation. Overall, 179 patients were divided into contrast enhancement model (n = 59), segmentation model (n = 120), and testing (n = 20) groups. The performance of the proposed model was evaluated using Dice similarity coefficient (DSC). The proposed model could achieve 0.97 ± 0.007 and 0.93 ± 0.002 DSC for aortic and pulmonary artery segmentation, respectively. The proposed model may provide 3D diameter information of the arteries before surgery, facilitating the estimation of pulmonary hypertension and supporting preoperative surgical method selection based on the predicted surgical risks.

[Targeted Therapy and Mechanism of Drug Resistance in Non-small Cell Lung Cancer with Epidermal Growth Factor Receptor Gene Mutation]

Lung cancer is the sixth leading cause of death worldwide and one of the leading cause of death from malignant tumors. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. Epidermal growth factor receptor (EGFR) gene mutation is a common mutation in NSCLC. For advanced NSCLC patients with EGFR mutations, EGFR-tyrosine kinase inhibitors (EGFR-TKIs), such as Gefitinib, Afatinib, Oxitinib and other targeted therapies have become the first-line treatment recommended by many guidelines, but many patients develop acquired drug resistance after about 1 year of medication. Patients with drug resistance will have earlier disease progression than patients without drug resistance, which has an important impact on the prognosis of patients. At present, the main treatment for patients with acquired resistance is new target inhibition for resistant mutation. For example, if patients with T790M mutation are resistant to the first or second generation drugs such as Gefitinb and Afatinib, they can be treated with the third generation drugs (Osimertinib or Almonertinib), which can delay the progression of the disease. Therefore, the study of drug resistance mechanism and treatment of drug resistance patients are essential. This paper mainly reviews targeted therapy and drug resistance mechanism of EGFR-mutant NSCLC patients, in order to provide reference for clinical application of EGFR-TKIs.
.

Small cell lung cancer transformation: From pathogenesis to treatment

Small cell lung cancer (SCLC) is a type of neuroendocrine tumor with high malignancy and poor prognosis. Besides the de novo SCLC, there is transformed SCLC, which has similar characteristics of pathological morphology, molecular characteristics, clinical manifestations and drug sensitivity. However, de novo SCLC and transformed SCLC have different pathogenesis and tumor microenvironment. SCLC transformation is one of the mechanisms of resistance to chemotherapy, immunotherapy, and targeted therapy in NSCLC. Two hypotheses have been used to explain the pathogenesis of SCLC transformation. Although SCLC transformation is not common in clinical practice, it has been repeatedly identified in many small patient series and case reports. It usually occurs in epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma after treatment with tyrosine kinase inhibitors (TKIs). SCLC transformation can also occur in anaplastic lymphoma kinase (ALK)-positive lung cancer after treatment with ALK inhibitors and in wild-type EGFR or ALK NSCLC treated with immunotherapy. Chemotherapy was previously used to treat transformed SCLC, yet it is associated with an unsatisfactory prognosis. We comprehensively review the advancements in transformed SCLC, including clinical and pathological characteristics, and the potential effective treatment after SCLC transformation, aiming to give a better understanding of transformed SCLC and provide support for clinical uses.

In-depth molecular analysis of combined and co-primary pulmonary large cell neuroendocrine carcinoma and adenocarcinoma

Up to 14% of large cell neuroendocrine carcinomas (LCNECs) are diagnosed in continuity with nonsmall cell lung carcinoma. In addition to these combined lesions, 1% to 7% of lung tumors present as co-primary tumors with multiple synchronous lesions. We evaluated molecular and clinicopathological characteristics of combined and co-primary LCNEC-adenocarcinoma (ADC) tumors. Ten patients with LCNEC-ADC (combined) and five patients with multiple synchronous ipsilateral LCNEC and ADC tumors (co-primary) were included. DNA was isolated from distinct tumor parts, and 65 cancer genes were analyzed by next generation sequencing. Immunohistochemistry was performed including neuroendocrine markers, pRb, Ascl1 and Rest. Pure ADC (N = 37) and LCNEC (N = 17) cases were used for reference. At least 1 shared mutation, indicating tumor clonality, was found in LCNEC- and ADC-parts of 10/10 combined tumors but only in 1/5 co-primary tumors. A range of identical mutations was observed in both parts of combined tumors: 8/10 contained ADC-related (EGFR/KRAS/STK11 and/or KEAP1), 4/10 RB1 and 9/10 TP53 mutations. Loss of pRb IHC was observed in 6/10 LCNEC- and 4/10 ADC-parts. The number and intensity of expression of Ascl1 and neuroendocrine markers increased from pure ADC (low) to combined ADC (intermediate) and combined and pure LCNEC (high). The opposite was true for Rest expression. In conclusion, all combined LCNEC-ADC tumors were clonally related indicating a common origin. A relatively high frequency of pRb inactivation was observed in both LCNEC- and ADC-parts, suggesting an underlying role in LCNEC-ADC development. Furthermore, neuroendocrine differentiation might be modulated by Ascl1(+) and Rest(-) expression.

Outcomes in Patients With Lung Adenocarcinoma With Transformation to Small Cell Lung Cancer After EGFR Tyrosine Kinase Inhibitors Resistance: A Systematic Review and Pooled Analysis

Background

Lung adenocarcinoma can transform into small-cell lung cancer (SCLC) when resistance to tyrosine kinase inhibitors (TKIs) develops. Approximately 3% to 10% of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) could transform to SCLC. This phenomenon has been described in several case reports and small patient series. However, the characteristics and treatment outcomes of this population have not been comprehensively reported, and their clinical course is poorly characterized.

Methods

We performed a systematic review of the published literature to summarize the clinical and pathological features and prognosis of the reported cases and analyzed the demographics, disease features, and outcomes.

Results

A total of 72 patients (50 females and 22 males) initially diagnosed with lung adenocarcinoma were included. EGFR mutations included 19-deletion (75%), L858R (22%), and G719X (3%). All patients received EGFR-TKIs before SCLC transformation. The median time from diagnosis to transformation was 20.5 months (95% CI, 15.45 to 26.55 months). Of the 67 patients with post-translational gene test results, 58 maintained their EGFR mutation, and only 1 of 18 with prior T790M positivity retained T790M mutation. After the pathological transformation, both conventional chemotherapy regimen and chemotherapy combined targeted therapy yielded high response rates. The disease control rate of first-line therapy after transformation was 76%, while the objective response rate was 48%. The median overall survival (OS) since diagnosis was 27 months (95% CI, 22.90 to 31.10 months), whereas median OS since SCLC transformation was 8.5 months (95% CI, 5.50 to 11.60 months).

Conclusion

The prognosis of transformed SCLC is worse than primary SCLC. The response rate to conventional chemotherapy was high. However, the progression-free survival and OS after transformation were short and the prognosis was poor with first-line therapies. New therapies are needed in the management of transformed SCLC.

[MDT Treatment of Small Cell Lung Cancer Complicated with Adenocarcinoma: A Case Report and Literature Review]

Small cell lung cancer (SCLC) is the most malignant lung cancer with the highest mortality. At present, the first-line standard treatment is still based on Etoposide and Platinum chemotherapy. However, for SCLC that progresses after first-line therapy, the treatment options are still very limited. Since the molecular mechanism of first-line drug resistance of SCLC is still unclear, and the precision medicine strategy after first-line drug resistance is still in the pre-clinical stage. The proportion of secondary biopsy and genetic testing is very low after the progress of first-line treatment of SCLC. In this study, we report a case of a middle-aged woman who was first diagnosed with SCLC. Adenocarcinoma with sensitive gene mutations and repeated changes of small cell carcinoma were detected by multiple biopsies during the course of the disease, suggesting that the patient may be a special subtype of SCLC - mixed SCLC (M-SCLC). In this case, the patient has been treated with radiotherapy and chemotherapy, immunotherapy and targeted therapy successively, and the survival time has reached 2 years and 8 months. Through the case report and literature review retrospectively, this study aimed to explore the part patients may start to present hybrid histopathologic types or tissue type change after treatment of SCLC. Biopsy pathologic histology and genetic testing is necessary after disease progression to look for potential therapeutic targets, so as to give precise treatment based on molecular markers detection results and provide the patient with the benefit of survival for as long as possible.
.

Small cell transformation of non-small cell lung cancer under immunotherapy: Case series and literature review

In advanced lung cancer treatment, immunotherapy provides durable responses in some patients. However, other patients experience progressive disease and the resistance mechanisms to immunotherapy have yet been fully elucidated. Small cell transformation of non‐small cell lung cancer (NSCLC) is commonly recognized as one of the resistance mechanisms to epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors in EGFR‐mutant NSCLC treatment. As a resistant mechanism for immunotherapy, we report the first case of small cell transformation in 2017. Since then, eight similar cases have been reported and the concept of small cell transformation is now becoming more prevalent as a mechanism of immunotherapy resistance. In our facility, we have experienced four cases of small cell transformation after immunotherapy (including the reported case in 2017). The histology of each primary tumor was squamous cell carcinoma, large cell type neuroendocrine carcinoma, or poorly differentiated NSCLC. None had driver gene mutations. Nivolumab was administered in all four cases and atezolizumab was administered as a next line to nivolumab treatment in one case. The best response to immunotherapy was partial response or stable disease. There was a wide range of periods from the start of immunotherapy to confirmation of small cell transformation (from 2 weeks to almost 3 years). In conclusion, small cell transformation is an important resistance mechanism in cancer immunotherapy. When NSCLC progresses after immunotherapy, the possibility of small cell transformation and rebiopsy should always be encouraged, as it leads to clarification of the resistance mechanisms and frequency.

Novel ETV1 mutation in small cell lung cancer transformation resistant to EGFR tyrosine kinase inhibitors

Background

Non-small cell lung cancer (NSCLC) patients harboring mutations in the epidermal growth factor receptor (EGFR) gene respond dramatically to EGFR tyrosine kinase inhibitors (TKIs). However, these patients inevitably develop acquired resistance to EGFR-TKIs. Among them, small cell lung cancer (SCLC) transformation is a relatively rare mechanism.

Methods

We used a 639 cancer-relevant gene panel to detect genetic differences in tissues before and after EGFR-TKIs resistance caused by SCLC transformation. In vitro experiments were conducted to study the role of ETS variant transcription factor 1 (ETV1) on SCLC transformation and EGFR-TKIs resistance.

Results

We present two EGFR-mutant lung adenocarcinoma (LUAD) patients. One patient, with EGFR exon 19 deletion (Ex19del), accepted first-line gefitinib treatment and then received osimertinib treatment due to acquisition of an EGFR-T790M mutation. A novel ETV1 mutation (p.P159S) was detected in the SCLC tissue after osimertinib resistance when not coexisting with T790M. The other patient harbored an EGFR exon 21 mutation (p.L858R), and had a long-lasting response to first-line gefitinib, and then transformed to SCLC after TKI resistance. A previously unreported ETV1 mutation (p.E462Q) was detected in the SCLC tissue. In vitro, ETV1 p.E462Q and p.P159S mutations participated in neuroendocrine differentiation by inducing the expression of achaete-scute homolog 1 (ASCL1) and promoting the proliferation of H69 cells. ETV1 p.E462Q and p.P159S mutations were also resistant to gefitinib and osimertinib after introduction into H358 cells.

Conclusions

Novel ETV1 p.E462Q and p.P159S mutations were found in the SCLC tissues of TKIs-resistant LUAD patients, providing a new understanding of ETV1 involvement in acquired resistance to EGFR-TKIs via SCLC transformation.

Small-cell lung cancer transformation from EGFR-mutant adenocarcinoma after EGFR-TKIs resistance: A case report

RATIONALE

With the recent advancements in molecular biology research, epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have emerged as excellent therapies for patients with EGFR-mutant cancers. However, these patients inevitably develop cross-acquired resistance to EGFR-TKIs. Transformation to small-cell lung cancer (SCLC) is considered a rare resistance mechanism against EGFR-TKI therapy. Here, we report a case of TKI resistance due to SCLC transformation and demonstrate its mechanisms and clinical features.

PATIENT CONCERNS

A 54-year-old Chinese man with a history of smoking for 40 years complained of an intermittent cough in March 2019.

DIAGNOSIS

Transbronchial lung biopsy was performed on the basal segment of the left lower lobe, which confirmed lung adenocarcinoma. In January 2020, repeat biopsy was performed, and the results of immunohistochemistry (IHC) staining showed TTF-1 (+), CK7 (+), napsin A (+), syn (+), and CD56 (+), with a Ki-67 (+) index 80% of small cell carcinomas. Infiltrating adenocarcinomas and small cell carcinomas were observed.

INTERVENTIONS

Icotinib (125 mg thrice daily) was administered as a first-line treatment from June 2019. We subsequently administered a chemotherapy regimen consisting of etoposide (180 mg, days 1-3) plus cisplatin (45 mg, days 1-3) every 3 weeks for 1 cycle after recurrence. As the patient could not tolerate further chemotherapy, he continued taking icotinib orally and received whole-brain radiotherapy 10 times to a total dose of 30 Gy after brain metastases.

OUTCOMES

The patient relapsed after successful treatment with icotinib for 9 months. A partial response was achieved after 4 cycles of chemotherapy, and despite the brief success of chemotherapy, our patient exhibited brain metastasis and metastases of the eleventh thoracic spine and the second lumbar vertebra with pathological fracture. The patient eventually died of aggressive cancer progression.

LESSONS

Our case highlights the possibility of SCLC transformation from EGFR-mutant adenocarcinoma and the importance of repeat biopsy for drug resistance. Serum neuron-specific enolase levels may also be useful for detecting early SCLC transformation.

Solubility Enhancement of Methotrexate by Solid Nanodispersion Approach for the Improved Treatment of Small Cell Lung Carcinoma

AIMS

The present work aimed to develop MT loaded solid Nano dispersion by improving its solubility, half-life and bioavailability in biological system thereby this formulation may be afforded economically.

BACKGROUND

Small cell lung carcinoma is a type of malignant tumor characterized by uncontrolled cell growth at lung tissues. The potent anti-cancer drug methotrexate (MT) chosen for the present work is poorly soluble in water (BCS type IV class) with short half-life and hepatotoxic effect.

OBJECTIVE

With the concept of polymeric surfactant to improve the solubility along with wettability of drugs, the present work has been hypothesized to improve its solubility using polyvinyl pyrollidone (PVP K30) polymer and α- tocopheryl polyethylene glycol 1000 succinate (TPGS) surfactant, thereby the bioavailability is expected to get enhanced. By varying the PVP K30 and TPGS ratios different formulations were developed using emulsification process.

METHODS

The developed MT loaded solid nanodispersion was further characterized for its particle size, charge, morphology, encapsulation efficiency and in-vitro release behavior etc. Results: The results of FT-IR spectrometric analysis indicated the compatibility nature of MTX, PVPK30 and TPGS. The developed formulations showed spherical morphology, particle size ranging from 59.28±24.2 nm to 169.33±10.85 nm with a surface charge ranging from -10.33 ± 2.81mV to -9.57 ± 1.2 mV. The in vitro release studies as performed by dialysis bag method showed a sustained release pattern as checked by UV Spectrophotometer. Residual solvent analysis for MTXNDs performed by HPLC indicates there is no residual DMSO in the formulation. Transmission electron microscopic image of MTXNDs revealed that the particles are spherical shaped with a solid core structure. Haemolytic assay indicates that the developed formulation is safe for intravenous administration. Cell culture studies in A549 cells indicates the enhanced cytotoxic effect for the developed formulation.

CONCLUSION

This proof of study indicates that the developed formulation may have anticancer potential for SCLC treatment.

Histological transformation of lung adenocarcinoma to small cell lung cancer with mutant C797S conferring acquired resistance to osimertinib

Epidermal growth factor receptor (EGFR) gene-mutated non-small cell lung cancer may initially respond to EGFR tyrosine kinase inhibitors (TKIs), but may subsequently become resistant; however, the resistance mechanisms remain unclear. We report a rare case of acquired resistance to osimertinib associated with transformation to small cell lung cancer (SCLC) with cis-C797S mutation. A man with recurrent lung adenocarcinoma harboring an EGFR exon 19 deletion received erlotinib for 10 months following curative surgery and adjuvant chemotherapy. However, he switched to osimertinib after repeat biopsy showed EGFR exon 19 deletion and T790M mutation leading to erlotinib resistance. His disease progressed after 15 months and repeat biopsy showed SCLC. Next-generation sequencing of peripheral blood detected EGFR exon 19 deletion, T790M mutation, cis-C797S mutation, and RB1 inactivation. The tumor was reduced after four cycles of etoposide and cisplatin and his respiratory symptoms improved. However, computed tomography after six cycles of chemotherapy showed multiple bilateral lung lesions, and single-photon emission computed tomography showed bone metastasis. The patient received paclitaxel plus cisplatin for two cycles with partial response. Because heterogeneous genetic and phenotypic mechanisms of TKI-resistance may occur at different times and locations, histopathological and molecular testing both provide evidence to support appropriate treatment.

Intratumoral Cellular Heterogeneity: Implications for Drug Resistance in Patients with Non-Small Cell Lung Cancer

Simple Summary

The number of druggable tumor-specific molecular alterations in the treatment of non-small cell lung cancer (NSCLC) has grown significantly in the past decade. Emerging technologies such as liquid biopsy and single-cell methods allow for studying targetable drivers and develop personalized treatments. However, although new therapies confer prolonged disease control and high tumor response rates, most patients eventually progress on targeted treatments. Intratumoral heterogeneity is a frequent event in NSCLC, driving the tumor cells to develop adaptive or new resistance mechanisms within the drug environment. This review summarizes the current and upcoming research on the biological role of tumor heterogeneity, highlighting the link between early and acquired drug resistance and tumoral heterogeneity in targetable driver mutated NSCLC.

Abstract

Tailored therapies based on the identification of molecular targets currently represent a well-established therapeutic scenario in the treatment of non-small cell lung cancer (NSCLC) patients. However, while aiming to improve patients’ response to therapy, development of resistance is frequently observed in daily clinical practice. Intratumoral heterogeneity is a frequent event in NSCLC, responsible for several critical issues in patients’ diagnosis and treatment. Advances in single-cell sequencing technologies have allowed in-depth profiling of tumors and attributed intratumoral heterogeneity to genetic, epigenetic, and protein modification driven diversities within cancer cell populations. This review highlights current research on the biological role of tumor heterogeneity and its impact on the development of acquired resistance in NSCLC patients.

Combination of tissue and liquid biopsy molecular profiling to detect transformation to small cell lung carcinoma during osimertinib treatment

Background:

Histological transformation of advanced non-small cell lung cancer (NSCLC) to small cell lung cancer (SCLC) is one of the mechanisms of resistance to third-generation tyrosine kinase inhibitors (TKIs), such as osimertinib. This acquired TKI resistance is linked to the high degree of tumor heterogeneity and adaptive cellular signaling pathways, including epidermal growth factor receptor (EGFR)-dependent pathways, observed in NSCLC.

Methods:

Here, we investigated a series of paired pre- and post-histological transformation biopsies obtained from three patients initially having a NSCLC with an EGFR^activating mutation treated with first-generation TKI, who then received osimertinib as second-line after EGFR^T790M resistance and, lastly, developed a histological transformation to SCLC. Both tissue and liquid biopsies were analyzed using large panel sequencing approaches at various time points to reconstruct the clonal evolutionary history of the tumor.

Results:

Our complementary analysis of tumor tissue and circulating tumor DNA samples allowed us to better characterize the histological and molecular alterations associated with resistance to osimertinib. SCLC transformation was linked to the presence of several concomitant gene alterations, including EGFR, TP53 and RB1, but also to specific signal bypass, such as EGFR and MET amplifications and activation of the PI3K/AKT/mTOR pathway.

Conclusion:

Our report emphasizes the mutational landscape of SCLC histological transformation and highlights the importance of combining tissue and liquid biopsy profiling before and during osimertinib treatment to predict such histological transformation.

Identification of RUNX1T1 as a potential epigenetic modifier in small-cell lung cancer

Small-cell lung cancer (SCLC) can be subgrouped into common 'pure' and rare 'combined' SCLC (c-SCLC). c-SCLC features a mixed tumor histology of both SCLC and non-small-cell lung cancer (NSCLC). We performed targeted exome sequencing on 90 patients with SCLC, including two with c-SCLC, and discovered RUNX1T1 amplification specific to small cell tumors of both patients with c-SCLC, but in only 2 of 88 'pure' SCLC patients. RUNX1T1 was first identified in the fusion transcript AML1/ETO, which occurs in 12%-15% of acute myelogenous leukemia (AML). We further show higher expression of RUNX1T1 in the SCLC component of another c-SCLC tumor by in situ hybridization. RUNX1T1 expression was enriched in SCLC compared with all other cancers, including NSCLC, in both cell lines and tumor specimens, as shown by mRNA level and western blotting. Transcriptomic analysis of hallmark genes decreased by stable RUNX1T1 overexpression revealed a significant change in E2F targets. Validation experiments in multiple lung cancer cell lines showed that RUNX1T1 overexpression consistently decreased CDKN1A (p21) expression and increased E2F transcriptional activity, which is commonly altered in SCLC. Chromatin immunoprecipitation (ChIP) in these overexpressing cells demonstrated that RUNX1T1 interacts with the CDKN1A (p21) promoter region, which displayed parallel reductions in histone 3 acetylation. Furthermore, reduced p21 expression could be dramatically restored by HDAC inhibition using Trichostatin A. Reanalysis of ChIP-seq data in Kasumi-1 AML cells showed that knockdown of the RUNX1T1 fusion protein was associated with increased global acetylation, including the CDKN1A (p21) promoter. Thus, our study identifies RUNX1T1 as a biomarker and potential epigenetic regulator of SCLC.

Combined small cell lung carcinoma harboring ALK rearrangement: A case report and literature review

Combined small cell lung cancer (c‐SCLC) is a relatively rare subtype of SCLC and is defined by the combination of SCLC and any elements of non‐small cell carcinoma (NSCLC). Standard chemotherapy for patients with c‐SCLC has not yet been established. Gene mutations such as epidermal growth factor receptor (EGFR) mutations may be detected in patients with c‐SCLC. However, little is known about anaplastic lymphoma kinase (ALK) rearrangement in c‐SCLC patients. Here, we report a young female patient who was successfully treated with alectinib for ALK‐positive c‐SCLC after failure of immunochemotherapy for SCLC and cytotoxic chemotherapy for adenocarcinoma. Moreover, we performed a literature review of EGFR‐ or ALK‐positive c‐SCLC patients. Our report suggests that ALK testing may be justified in patients with SCLC that contain an adenocarcinoma component.

Key points

Significant findings of the study

• This is the first report describing the treatment course comprising immunochemotherapy and ALK‐TKI in a patient with c‐SCLC harboring ALK rearrangement.

What this study adds

• Our case and literature review suggest that although ALK mutation is rare in patients with c‐SCLC, its identification and treatment with ALK‐TKIs may contribute to clinical benefits.

Deep Learning for the Classification of Small-Cell and Non-Small-Cell Lung Cancer

Reliable entity subtyping is paramount for therapy stratification in lung cancer. Morphological evaluation remains the basis for entity subtyping and directs the application of additional methods such as immunohistochemistry (IHC). The decision of whether to perform IHC for subtyping is subjective, and access to IHC is not available worldwide. Thus, the application of additional methods to support morphological entity subtyping is desirable. Therefore, the ability of convolutional neuronal networks (CNNs) to classify the most common lung cancer subtypes, pulmonary adenocarcinoma (ADC), pulmonary squamous cell carcinoma (SqCC), and small-cell lung cancer (SCLC), was evaluated. A cohort of 80 ADC, 80 SqCC, 80 SCLC, and 30 skeletal muscle specimens was assembled; slides were scanned; tumor areas were annotated; image patches were extracted; and cases were randomly assigned to a training, validation or test set. Multiple CNN architectures (VGG16, InceptionV3, and InceptionResNetV2) were trained and optimized to classify the four entities. A quality control (QC) metric was established. An optimized InceptionV3 CNN architecture yielded the highest classification accuracy and was used for the classification of the test set. Image patch and patient-based CNN classification results were 95% and 100% in the test set after the application of strict QC. Misclassified cases mainly included ADC and SqCC. The QC metric identified cases that needed further IHC for definite entity subtyping. The study highlights the potential and limitations of CNN image classification models for tumor differentiation.

Current Strategies for Treating NSCLC: From Biological Mechanisms to Clinical Treatment

The identification of specific epidermal growth factor receptor (EGFR)-activating mutations heralded a breakthrough in non-small-cell lung cancer (NSCLC) treatments, with the subsequent development of EGFR-tyrosine kinase inhibitor (TKIs) becoming the first-line therapy for patients harboring EGFR mutations. However, acquired resistance to EGFR-TKIs inevitably occurs in patients following initial TKI treatment, leading to disease progression. Various mechanisms are behind the acquired resistance, and mainly include (1) target gene modification, (2) alternative parallel pathway activation, (3) downstream pathway activation, and (4) histological/phenotypic transformation. Approaches to combat the acquired resistance have been investigated according to these mechanisms. Newer generations of TKIs have been developed to target the secondary/tertiary EGFR mutations in patients with acquired resistance. In addition, combination therapies have been developed as another promising strategy to overcome acquired resistance through the activation of other signaling pathways. Thus, in this review, we summarize the mechanisms for acquired resistance and focus on the potential corresponding therapeutic strategies for acquired resistance.

Prognostic value of TP53 concurrent mutations for EGFR- TKIs and ALK-TKIs based targeted therapy in advanced non-small cell lung cancer: a meta-analysis

Background

The prognostic significance of TP53 concurrent mutations in patients with epidermal growth factor receptor (EGFR)- or anaplastic lymphoma kinase (ALK)- mutated advanced non–small-cell lung cancer (NSCLC) who received EGFR-tyrosine kinase inhibitors (TKIs) or ALK-TKIs based targeted therapy remains controversial. Therefore, the present meta-analysis was performed to investigate the association between TP53 concurrent mutations and prognosis of patients with advanced NSCLC undergoing EGFR-TKIs or ALK-TKIs treatments.

Methods

Eligible studies were identified by searching the online databases PubMed, Embase, Medline, The Cochrane library and Web of Science. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to clarify the correlation between TP53 mutation status and prognosis of patients. This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

In total, 15 studies with 1342 patients were included for final analysis. Overall, concurrent TP53 mutation was associated with unfavorable progression-free survival (PFS) (HR = 1.88, 95%CI: 1.59–2.23, p < 0.001, I² = 0.0%, P = 0.792) and overall survival (OS) (HR = 1.92, 95%CI: 1.55–2.38, p < 0.001, I² = 0.0%, P = 0.515). Subgroup analysis based on type of targeted therapy (EGFR-TKIs or ALK-TKIs, pathological type of cancer (adenocarcinoma only or all NSCLC subtypes) and line of treatment (first-line only or all lines) all showed that TP53 mutations was associated with shorter survivals of patients with EGFR-TKIs or ALK-TKIs treatments. Particularly, in patients with first-line EGFR-TKIs treatment, significantly poorer prognosis was observed in patients with TP53 concurrent mutations (pooled HR for PFS: 1.69, 95% CI 1.25–2.27, P < 0.001, I² = 0.0%, P = 0.473; pooled HR for OS: 1.94, 95% CI 1.36–2.76, P < 0.001, I² = 0.0%, P = 0.484). Begg’s funnel plots and Egger’s tests indicated no significant publication bias in this study.

Conclusions

This meta-analysis indicated that concurrent TP53 mutations was a negative prognostic factor and associated with poorer outcomes of patients with EGFR-TKIs or ALK-TKIs treatments in advanced NSCLC. In addition, our study provided evidence that TP53 mutations might be involved in primary resistance to EGFR-TKIs treatments in patients with sensitive EGFR mutations in advanced NSCLC.

Inhibitor of Differentiation 1 (ID1) Facilitates the Efficacy of Sorafenib in Non-Small Cell Lung Cancer Cells through Suppressing Epithelial to Mesenchymal Transition

BACKGROUND Sorafenib, which is a multitargeted kinase inhibitor, has shown some antitumor effects in patients with non-small cell lung cancer (NSCLC). However, the potential target of sorafenib's antitumor activity is largely unknown. Moreover, definitive predictive biomarkers of benefit have rarely been reported. MATERIAL AND METHODS The alteration in inhibitor of differentiation 1 (ID1) expression in NSCLC cells with sorafenib treatment was detected by western blotting. The sensitivity of NSCLC cells to sorafenib was observed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) assay. Loss-of-function and gain-of-function experiments were performed to observe the role of ID1 expression in epithelial to mesenchymal transition (EMT) progression. RESULTS Initially, we observed that ID1 was downregulated in NSCLC cells treated with sorafenib. The response of NSCLC cells to sorafenib was inhibited by the transfection of small interfering RNAs (siRNAs) targeting ID1. In contrast, the transfection of ID1-overexpressing plasmids improved the response of NSCLC cells to sorafenib. Further experiments indicated that ID1 is expressed at high levels in epithelial H460 cells and expressed at low levels in mesenchymal H358 cells. Loss-of-function and gain-of-function experiments suggested that ID1 negatively regulates EMT in NSCLC. CONCLUSIONS The expression of ID1 is dose-dependently inhibited by sorafenib, and the overexpression of ID1 contributes to the antitumor activity of sorafenib by suppressing EMT development. Our results indicate that ID1 might be a potential target for the antitumor activity of sorafenib in NSCLC and that targeting ID1 is a feasible strategy to improve the sensitivity of NSCLC cells to sorafenib.

Lung adenocarcinoma with sarcomatoid transformation after tyrosine kinase inhibitor treatment and chemotherapy

OBJECTIVES

Lung cancers have various acquired resistance mechanisms that lead to treatment failure and disease progression, including secondary epidermal growth factor receptor (EGFR) exon 20 T790 M mutations, EGFR downstream or bypass pathway activation, and histologic transformation from adenocarcinoma to small cell carcinoma, squamous cell carcinoma, or sarcomatoid carcinoma.

MATERIALS AND METHODS

This study compared the pathological and immunohistochemical characteristics before and after sarcomatoid transformation. Six advanced cases of lung adenocarcinoma that developed sarcomatoid transformation after treatment were collected.

RESULTS

Five cases had classic EGFR mutations and one had a ROS1 rearrangement. The interval from initial diagnosis to sarcomatoid transformation ranged from 9 to 88 mo (median of 31.5 mo). The median survival after sarcomatoid transformation was 2.5 mo (1-16 mo). Before sarcomatoid transformation, all cases demonstrated typical adenocarcinoma features, including acinar, micropapillary, or solid/cribriform patterns, negative or weak focal vimentin staining, and strong E-cadherin expression. Histologic features of sarcomatoid transformation included giant cell features (6/6), loose cellular cohesion (6/6), strong staining for vimentin (6/6), decreased or lost E-cadherin expression (5/6), and high PD-L1 expression (5/6; one case demonstrated high PD-L1 staining at initial diagnosis). High MET expression and MET copy number gain (two samples with high polysomy and three with true amplification) were observed in five cases with EGFR mutation treated with tyrosine kinase inhibitors (TKI). One case exhibited MET amplification prior to the start of TKI treatment.

CONCLUSION

Sarcomatoid transformation is a type of lung cancer histologic evolution with a poor prognosis and a high proportion of cases with aberrant MET activation and PD-L1 expression.