SKOR Antibody

Definition and Biological Role

SKOR antibodies are immunoglobulin G (IgG) autoantibodies that bind to the SKOR2 protein, a neural-specific antigen expressed in tumors. SKOR2 is involved in transcriptional regulation and is expressed in cerebellar neurons, particularly at the Purkinje cell-granule cell junction . These antibodies are detected in patients with PNS, where the immune system mistakenly targets neural antigens expressed by cancerous cells .

Key Studies

A 2023 study identified SKOR2 IgG using programmable phage immunoprecipitation sequencing (PhIP-Seq) in two patients with adenocarcinoma and progressive neurological symptoms :

• Validation Methods:

  • Tissue Immunofluorescence (IFA): Demonstrated nuclear staining at the Purkinje cell-granule cell junction .

  • Recombinant CBA: Confirmed SKOR2-specific IgG binding in transfected COS7 cells .

  • Western Blot: Detected a 130-kD band in SKOR2-expressing lysates .

Cancer Association

• SKOR2 expression was confirmed in lung adenocarcinoma tissue via immunohistochemistry .

• No reactivity was observed in 30 adenocarcinoma patients without PNS, supporting its specificity .

Diagnostic and Prognostic Significance

• Biomarker Utility: SKOR2 IgG serves as a high-risk paraneoplastic marker, with malignancy association rates potentially exceeding 70% .

• Testing Protocols:

  1. Tissue IFA: Screening for cerebellar staining patterns.

  2. CBA/Western Blot: Confirmatory testing for SKOR2 specificity .

• Limitations: Small cohort size (two cases) and phenotypic variability necessitate further validation .

Future Directions

• Larger studies are needed to define the full clinical spectrum and optimize detection methods.

• SKOR2’s role in tumor immunology and neural cross-reactivity remains under investigation .