Test Catalog

Test ID: DLL3    
Delta-Like 3 Protein (SP347), Semi-Quantitative Immunohistochemistry, Manual, Tissue

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of small cell lung carcinoma (SCLC), large cell neuroendocrine carcinoma (LCNEC), amongst other tumors

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Delta-like 3 protein (DLL3) is an atypical Notch ligand induced by the neuroendocrine transcription factor, ASCL-1.  DLL3 is expressed on the cell membrane and in the cytoplasm of tumor cells. 

Interpretation Provides information to assist in interpretation of the test results

Positivity for this test will require 50% or more of the tumor cells within a specimen to express delta-like 3 protein with an intensity ranging from 1 to 3+.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen-dependent. Best practice is for paraffin sections to be cut fresh.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Saunders LR, Bankovich AJ, Anderson WC, et al: A DLL3-targeted antibody-drug conjugate eradicates high-grade pulmonary neuroendocrine tumor-initiating cells in vivo. Sci Transl Med. 2015 Aug;7(302):302ra136

2. Xie H, Boland JM, Maleszewski JJ, et al: Expression of delta-like protein 3 is reproducibly present in a subset of small cell lung carcinomas and pulmonary carcinoid tumors. Lung Cancer. 2019 Sep;135:73-79. doi: 10.1016/j.lungcan.2019.07.016

3. Xie H, Kaye FJ, Isse K, et al: Delta-like protein 3 expression and targeting in merkel cell carcinoma. Oncologist. 2020 Sep 1;10:810-817. doi: 10.1634/theoncologist.2019-0877