Anti-PRAME (clone QR005)

PRAME – A Cancer-Associated Antigen for Melanocytic Lesion Differentiation
PRAME (Preferentially Expressed Antigen in Melanoma) is a cancer-associated antigen preferentially expressed in the nuclei of neoplastic melanocytes. The newly developed anti-PRAME antibody serves as a valuable diagnostic tool, particularly in cases where traditional melanoma markers such as HMB-45, Melan A, and SOX10 do not provide sufficient information for differentiating benign and malignant melanocytic lesions. Additionally, PRAME may serve as a useful marker for assessing margins in known PRAME-positive melanomas.
Sebaceous gland lobules can act as an internal positive control.
Diagnostic Relevance of PRAME in Melanoma
Recent studies indicate that diffuse nuclear immunoreactivity for PRAME is observed in:
✔ 83.2% of primary melanomas
✔ 87% of metastatic melanomas
PRAME expression is present across all melanoma subtypes:
✔ 92.5% in superficial spreading melanoma
✔ 94.4% in acral melanoma
In contrast, 86.4% of cutaneous melanocytic nevi exhibit a complete absence of PRAME staining, reinforcing its significance in distinguishing benign from malignant lesions.
PRAME as a Cancer-Testis Antigen and Immunotherapy Target
PRAME was first identified as a cancer-testis antigen (CTA) through T-cell clone analysis from a patient with metastatic melanoma. Its expression is absent in normal tissues, except for the testes, ovaries, placenta, adrenal glands, and endometrium.
Beyond melanoma, PRAME is expressed in multiple non-melanocytic malignancies, including:
✔ Non-small cell lung carcinoma (NSCLC)
✔ Breast cancer
✔ Renal cell carcinoma
✔ Ovarian cancer
✔ Leukemias
✔ Synovial sarcoma
✔ Myxoid liposarcoma
Due to its distinct expression profile, PRAME is an attractive target for immunotherapy. Numerous clinical trials are underway to explore the potential of CTA-targeted therapies, including PRAME, in cancer treatment.
In addition to its role as a therapeutic target in metastatic melanoma, PRAME is also recognized as a biomarker for metastatic risk in class 1 uveal melanoma.