Genetic heterogeneity and predictive biomarker for pulmonary sarcomatoid carcinomas

A Metastatic Pulmonary Sarcomatoid Carcinoma Patient Harboring KIF5B-RET Fusion Responds to First-Line Pralsetinib Treatment: A Case Report

Pulmonary sarcomatoid carcinoma (PSC) is a rare subtype of non-small cell lung cancer (NSCLC), accounting for about 1% of cases. These tumors are characterized by their high malignancy and frequent resistance to chemotherapy, resulting in a worse prognosis compared to other NSCLC subtypes. Currently, there is no established therapeutic strategy for PSC. Recent advancements in targeted therapies have led to the development of ret proto-oncogene (RET) inhibitors, such as selpercatinib and pralsetinib, which have been approved for the treatment of RET fusion-positive NSCLC patients. Despite their effectiveness in RET fusion-positive NSCLC is observed, the efficacy of these inhibitors in PSC remains unclear. In this context, we present a case of metastatic PSC harboring de novo KIF5B-RET fusion. The patient responded to first-line trametinib treatment. These findings suggest that RET inhibitors could be a potential treatment option for metastatic PSC patients with RET fusion-positive tumors.

The efficacy and safety analysis of first-line immune checkpoint inhibitors in pulmonary sarcomatoid carcinoma

Background

Pulmonary sarcomatoid carcinoma (PSC) is a rare and aggressive disease without standardized treatment strategies. The efficacy of second-line or beyond immune checkpoint inhibitors (ICIs) has been proven in recent studies, whereas the evidence for first-line immunotherapy for PSC is still limited to case reports and remains poorly understood.

Materials and methods

This was a multicenter, retrospective analysis of 21 patients with a histological diagnosis of PSC who received ICI as first-line therapy from January 2019 to March 2022. The expression of PD-L1 was evaluated by immunohistochemistry (IHC) using the monoclonal antibody 22C3. Low and high PD-L1 expressions were defined using the tumor proportion score (TPS), with cutoffs of 1 and 50%, respectively.

Results

All eight patients had PD-L1 positivity who underwent PD-L1 expression assessment, and six patients (6/8, 75.0%) had high PD-L1 expression. Among the 21 PSC patients, seven received tislelizumab, six received camrelizumab, four received sintilimab, three received pembrolizumab, and one received durvalumab. Among them, 18 PSCs received combination therapy, whereas another three PSCs received immunotherapy alone. Out of the 21 PSC patients, 12 (57.1%) achieved a partial response (PR), and five patients had stable disease (SD) as the best response, whereas four PSCs experienced dramatic progressive disease (PD). The median progression-free survival (PFS) was 9.2 (95% CI [4.3, 14.1]) months, and the median OS was 22.8 (95% CI [4.0, 41.5]) months. Among the three treatment groups (immunotherapy alone, immunotherapy combined with anlotinib, and chemoimmunotherapy), the median PFS was 8.0, 9.4, and 9.6 months, and the median OS was 19.0, 22.8, and 30.6 months, respectively. There was no difference in PFS and OS between the three treatment regimen groups (P = 0.86 and P = 0.34, respectively) and different immunotherapies (P = 0.10 and P = 0.23, respectively). No serious adverse events (grade ≥ 3) were noted.

Conclusion

First-line immunotherapy has promising therapeutic potential in the treatment of PSC. More studies are warranted to confirm these findings.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

Molecular and expressional characterization of tumor heterogeneity in pulmonary carcinosarcoma

The genetic concordance and heterogeneity of the two components of pulmonary carcinosarcoma (PCS), carcinoma, and sarcoma, have not been fully elucidated because of its rare occurrence. We performed targeted sequencing of the carcinoma and sarcoma components of four PCSs to identify genetic similarities and differences. Formalin-fixed paraffin-embedded tissue samples were macroscopically or microscopically dissected. DNA was extracted from each component, and genetic alterations were analyzed separately. Moreover, we performed RNA-seq analysis on both components of one PCS to compare differences in gene expression profiles. The carcinoma part consisted of adenocarcinoma in two cases, squamous cell carcinoma in one, and adenosquamous carcinoma in the last. TP53 mutation was observed in three samples from the trunk, although it was detected only in the sarcoma part in one case. No specific driver gene mutation was observed; however, KRAS mutations were observed in one case in the trunk. RNA-seq analysis revealed that the rhabdomyosarcoma component expressed various genes related to muscle development, whereas the carcinoma component did not; and that gene expression overall was completely different between the two components. Our study revealed that the two different components of PCS shared common gene mutations in most cases. Although gene expression was different among components, if driver genes such as KRAS were detected in PCS, molecular targeted therapy could be beneficial even when the tumor contains a sarcoma component.

Multimodality Treatment of Pulmonary Sarcomatoid Carcinoma: A Review of Current State of Art

Pulmonary sarcomatoid carcinoma (PSC) is an unconventional non-small-cell lung cancer (NSCLC) that is currently managed under guidelines used for conventional NSCLC and has poor survival. Surgery is the optimal choice for resectable PSC, and the prevalence of mutations in this type of tumor laid the foundation for novel systemic therapies such as targeted therapy and immunotherapy. PSC is resistant to chemotherapy and radiotherapy, and the effects of the 2 therapies are controversial. Targeted therapies have been reported to confer survival benefits, and savolitinib, an oral selective MET tyrosine-kinase inhibitor, has been approved in metastatic patients with MET exon 14 skipping mutations. Expression and positive rate of programmed death ligand 1 in PSC are high; our previous research has also revealed a high mutational burden and a T-cell-inflamed microenvironment of PSC. Correspondingly, immune checkpoint inhibitors have shown preliminary antitumor effects (overall response rates of 40.5% (15/37) and 31.6% (6/19) in two retrospective studies, respectively) in PSC patients. In summary, patients should receive operations at an early stage and multimodality treatments are needed to maximize the benefits of patients with advanced disease.

The treatment of advanced pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid carcinoma (PSC) is a pathological subtype of non-small cell lung cancer. Although the incidence of PSC in lung cancer is very low, it is an aggressive cancer, leading to a poor prognosis. Currently, there is no standard treatment for advanced PSC. Targeted therapy can be used for patients with MET exon 14 mutations and patients with other driver gene mutations may also benefit from treatment. The emergence of immune checkpoint inhibitors also provides potential options for advanced PSC treatment, but more clinical data is needed. Additionally, more research may be warranted to explore the effects of chemotherapy, radiotherapy and antiangiogenic therapy. In this review, the authors summarize the research regarding the treatment of advanced PSC.

Survival Analysis and Prediction Model for Pulmonary Sarcomatoid Carcinoma Based on SEER Database

Objective

This study aimed to investigate the incidence of the pulmonary sarcomatoid carcinoma (PSC), to compare the clinical characteristics and overall survival (OS) of patients with PSC and those with other non-small-cell lung cancer (oNSCLC), so as to analyze the factors affecting the OS of patients with PSC and construct a nomogram prediction model.

Methods

Data of patients with PSC and those with oNSCLC diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results database were collected. The age-adjusted incidence of PSC was calculated. The characteristics of patients with PSC and those with oNSCLC were compared, then the patients were matched 1:2 for further survival analysis. Patients with PSC were randomly divided into training set and testing set with a ratio of 7:3. The Cox proportional hazards model was used to identify the covariates associated with the OS. Significant covariates were used to construct the nomogram, and the C-index was calculated to measure the discrimination ability. The accuracy of the nomogram was compared with the tumor–node–metastasis (TNM) clinical stage, and the corresponding area under the curve was achieved.

Results

A total of 1049 patients with PSC were enrolled, the incidence of PSC was slowly decreased from 0.120/100,000 in 2004 to 0.092/100,000 in 2015. Before PSM, 793 PSC patients and 191356 oNSCLC patients were identified, the proportion of male, younger patients (<65 years), grade IV, TNM clinical stage IV was higher in the PSC. The patients with PSC had significantly poorer OS compared with those with oNSCLC. After PSM, PSC still had an extremely inferior prognosis. Age, sex, TNM clinical stage, chemotherapy, radiotherapy, and surgery were independent factors for OS. Next, a nomogram was established based on these factors, and the C-indexs were 0.775 and 0.790 for the training and testing set, respectively. Moreover, the nomogram model indicated a more comprehensive and accurate prediction than the TNM clinical stage.

Conclusions

The incidence of PSC was slowly decreased. PSC had a significantly poor prognosis compared with oNSCLC. The nomogram constructed in this study accurately predicted the prognosis of PSC, performed better than the TNM clinical stage.