Concordance of ASCL1, NEUROD1 and POU2F3 transcription factor-based subtype assignment in paired tumour samples from small cell lung carcinoma

Phase I/II Investigator-Initiated Study of Olaparib and Temozolomide in SCLC: Final Analysis and CNS Outcomes

PURPOSE

Temozolomide plus PARP inhibition has shown promise in small cell lung cancer (SCLC). We previously reported outcomes from the first 50 patients (cohort 1) of a phase I/II trial of olaparib/temozolomide in recurrent SCLC. In this study, we report a final analysis of this trial, including a second cohort with an alternate dosing strategy and an exploratory analysis of central nervous system (CNS)-specific outcomes.

PATIENTS AND METHODS

This was an open-label phase I/II trial testing the combination of olaparib and temozolomide in relapsed SCLC. The primary endpoint was objective response rate (ORR). Secondary endpoints were safety, progression-free survival, and overall survival. We tested escalating doses of olaparib/temozolomide across two cohorts, both of which had temozolomide dosed on days 1 to 7 of each 21-day cycle. In previously published cohort 1, olaparib was dosed on days 1 to 7; in cohort 2, olaparib was dosed continuously.

RESULTS

Sixty-six patients were enrolled across the two cohorts: 50 in cohort 1 and 16 in cohort 2. The confirmed ORR of cohort 1 was 41.7% (20/48 evaluable), and the confirmed ORR of cohort 2 was 7% (1/14 evaluable; closed after dose escalation to enrollment for lack of observed efficacy). Among 15/66 patients (22.7%) with untreated brain metastases at enrollment, the best overall intracranial response was complete response in 6/15 patients, partial response in 4/15 patients, and stable disease in 3/15 patients for a CNS disease control rate of 87% (95% confidence interval, 59.5%-98.3%).

CONCLUSIONS

Olaparib/temozolomide may be effective in relapsed SCLC, especially for patients with CNS disease. Ongoing analyses with regard to optimal dosing schedule will inform potential for future use of this combination in SCLC.

Comparison of molecular subtype composition between independent sets of primary and brain metastatic small cell lung carcinoma and matched samples

INTRODUCTION

Recent advances in the subclassification of small cell lung carcinomas (SCLCs) may help to overcome the unmet need for targeted therapies and improve survival. However, limited information is available on how the expression of the subtype markers changes during tumour progression. Our study aimed to compare the expression of these markers in primary and brain metastatic SCLCs.

MATERIALS AND METHODS

Immunohistochemical analysis of the subtype markers was performed on 120 SCLCs (including 10 matched samples) and SCLC xenografts.

RESULTS

Compared to primary SCLCs, there was a significant increase in the proportion of mixed subtypes in brain metastases, with a rate of ASCL1high/NeuroD1high and ASCL1high/NeuroD1high/YAP1high subtypes increasing to 48 % and 18 %, respectively. The subtype of the paired samples matched in only one-third of the cases. Although we did not observe a significant change after chemotherapy, a continuous decrease in ASCL1 expression coupled with an increase in the NeuroD1 expression was detected in the xenografts in a long-term experiment.

DISCUSSION

Our results indicate that the expression of subtype markers frequently changes during disease progression, and subtype analysis of the primary SCLC may not provide accurate information about the characteristics of the recurrent or metastatic tumour. Therefore, repeated sampling and subtyping may be necessary for subtype-specific targeted therapy.

The molecular subtypes of small cell lung cancer defined by key transcription factors and their clinical significance

BACKGROUND

Lung cancer, a prevalent and deadly malignancy, is classified into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). SCLC is further subdivided into four molecular subtypes-SCLC-A, SCLC-N, SCLC-P, and SCLC-I-based on key transcription factor expression.

METHODS

Immunohistochemistry (IHC) was used to assess ASCL1, NEUROD1, and POU2F3 expression in tumor tissues. The H-Score quantified these results. Clinical characteristics, overall survival (OS), progression-free survival (PFS), and treatment responses were analyzed by subtype, and sensitivity to different treatments was assessed. Risk factors were identified through univariate and multivariate analyses.

RESULTS

IHC and H-Score analysis showed that POU2F3 expression was mutually exclusive with ASCL1 or NEUROD1. Subtype distribution was as follows: SCLC-A (40 %), SCLC-N (33 %), SCLC-P (7 %), and SCLC-I (20 %). There were no significant differences in baseline characteristics, OS (p = 0.829), or PFS (p = 0.924) among subtypes. However, the SCLC-I subtype showed a trend toward improved outcomes with platinum-based doublet chemotherapy plus immune checkpoint inhibitors. Multivariate COX regression identified M stage (HR: 1.72, 95 % CI: 1.13-2.63, p = 0.012) and bone metastasis at diagnosis (HR: 1.58, 95 % CI: 1.02-2.43, p = 0.040) as independent risk factors.

CONCLUSION

This study confirmed the SCLC subtyping based on key transcription factors. While no significant differences in OS and PFS among subtypes were found, the SCLC-I subtype showed potential benefit from platinum-based chemotherapy combined with immune checkpoint inhibitors. M stage and bone metastasis at diagnosis were identified as independent risk factors for SCLC.

Characteristics of molecular subtypes and cinical outcomes in the immunotherapy Queue of extensive-stage small cell lung cancer patients

BACKGROUND

With a series of clinical trials confirming the sensitivity of small cell lung cancer (SCLC) to immunotherapy, research on personalized treatment for SCLC has gained increasing attention. Currently, the most widely accepted subtype of SCLC is based on the expression levels of Achaete-Scute Family BHLH Transcription Factor 1 (ASCL1), neurogenic differentiation factor 1 (NEUROD1), and POU class 2 homeobox 3 (POU2F3). However, real-world studies on this classification remain limited.

METHODS

We retrospectively collected biopsy specimens from patients who received immunotherapy at Shandong Provincial Hospital between January 2019 and July 2021. After determining the patient subtypes using immunohistochemistry, we analyzed the relationships between each subtype and survival as well as some clinical characteristics.

RESULTS

In our study, we found that the subtype I achieved a significant survival advantage compared to the other groups. Additionally, the subtype A demonstrated a significant survival disadvantage. Among patients in the subtype I, there was a higher proportion of early brain metastasis and patients with a family history of tumors, while the subtype A had a lower proportion. Furthermore, the subtype A exhibited relatively poor immune infiltration.

CONCLUSION

In a diverse cohort of SCLC patients receiving immunotherapy, the subtype-I showed significant survival advantages while the subtype-A experienced a worse survival.

Top IHC/ISH Hacks for and Molecular Surrogates of Poorly Differentiated Sinonasal Small Round Cell Tumors

BACKGROUND

Poorly differentiated sinonasal small round cell tumors (SRCTs) are rare and heterogeneous, posing challenges in diagnosis and treatment.

METHODS

Recent advances in molecular findings and diagnostic refinement have promoted better understanding and management of these tumors.

RESULTS

The newly defined and emerging sinonasal entities demonstrate diverse morphologies, specific genomic signatures, and clinical behavior from conventional counterparts. In this review of SRCTs, emphasis is placed on the diagnostic approach with the employment of a pertinent panel of immunohistochemistry studies and/or molecular tests, fine-tuned to the latest WHO 5 classification of sinonasal/paranasal tumors and personalized treatment.

CONCLUSION

Specifically, this review focuses on tumors with epithelial and neuroectodermal derivation.