What question did this study set out to answer?

This research examines the prognostic value of the biomarker panel including OTP, CD44, and Ki-67 in preoperative lung carcinoid biopsies.

April 5, 2026

Abstract 7215: The OTP, CD44, Ki67 biomarker panel predicts prognosis in preoperative lung NET biopsy specimens

Key Points

This research examines the prognostic value of the biomarker panel including OTP, CD44, and Ki-67 in preoperative lung carcinoid biopsies.
Selected patients with lung carcinoids from Dutch pathology archives
Performed immunohistochemistry for OTP, CD44, and Ki-67 on biopsy specimens
Pathology reviewed by three experts according to WHO 2021 classification
Applied H-score for OTP and CD44 and eyeball estimation for Ki-67 proliferation index
Biomarker panel identified 89% of relapsed patients as high-risk, outperforming WHO classification
The negative predictive value of the biomarker panel was 0.96 compared to 0.82 for WHO
Higher inter-rater agreement for biomarker panel (κ=0.673) compared to WHO (κ=0.276)
Improved inter-specimen concordance for biomarker panel (κ=0.584) versus WHO (κ=0.169)

Abstract

Abstract Introduction: Previously OTP, CD44 and Ki-67 have been identified as prognostic biomarkers in resected lung neuroendocrine tumors (lung NETs, also known as lung carcinoids (LCs)). Aims: We aimed to examine the prognostic value of biomarkers OTP, CD44 and Ki-67 in preoperative LC biopsies. Methods: Patients with LC (reclassified TNM 8 stage I-III, 2003-2022) who underwent a curative resection were selected from Dutch pathology archives (PALGA). Matching resection (Rx) and biopsy (Bx) specimens were identified and immunohistochemistry (IHC) for OTP, CD44 and Ki-67 was performed. Pathology revision was carried out by three pathologists according to the WHO 2021 classification. OTP and CD44 immunostaining were assessed (H-score), and Ki-67 proliferation index (PI) by eyeball estimation with hot-spot scoring. Bx cases diagnosed as typical carcinoid (TC) or carcinoid not otherwise specified (NOS) were grouped as low risk (i.e. non-atypical carcinoid or non-AC). The biomarker panel was classified as low-risk (OTP≥50, CD44≥30, Ki-675%) or high-risk (all others). Results: In total 98 patients were eligible, including 19 patients with a relapse after a median follow-up of 83.3 months. The biomarker panel correctly identified high-risk in 89% (n=17/19) of relapses, outperforming WHO classification, which assigned only 11% (n=2/19) of relapses as AC. Negative predictive value (NPV) of the biomarker panel was 0.96 compared to 0.82 for WHO. Biomarker risk stratification also showed higher inter-rater agreement (biomarker panel: κ=0.673; WHO: κ=0.276, both p0.001) and improved inter-specimen concordance (biomarker panel: κ=0.584, p0.001; WHO: κ=0.169, p=0.037). Conclusion: An OTP, CD44 and Ki-67 IHC biomarker panel substantially improves identification of patients with low-risk LCs and is applicable on biopsy specimens, outperforming the prognostic value of WHO classification. This may influence the choice of surgical treatment strategy. Citation Format: Tijmen JJ van Weert, Laura Moonen, Lisa M. Hillen, Jan von der Thüsen, Michael A. den Bakker, Lisa MV Lap, PALGA Group, Ronald A. Damhuis, Wieneke A. Buikhuisen, Anne-Marie C. Dingemans, Jules L. Derks, Ernst Jan M. Speel. The OTP, CD44, Ki67 biomarker panel predicts prognosis in preoperative lung NET biopsy specimens abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7215.

Mark Helpful

Bookmark

Relay