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Published on: March 8, 2022
Diagnostic and Prognostic Values of PRAME Immunohistochemistry in Acral Lentiginous Melanoma
Korn Triyangkulsri1, Namthong Wittayabusarakam1, Supachak Smitthisakda1
1Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Background:
PReferentially Expressed Antigen in MElanoma (PRAME) was introduced as an ancillary tool for confirming the diagnosis of cutaneous melanoma, including the acral lentiginous melanoma (ALM). However, its standardized cut-off values and prognostic performance remain inconclusive. This study assessed the diagnostic performance of PRAME immunohistochemistry (IHC) in ALM across different thresholds and explored its prognostic associations.
Methods:
This retrospective cohort study reviewed 90 acral melanocytic lesions, including 60 cases of acral benign nevi and 30 cases of primary ALM. PRAME immunohistochemistry was performed on the biopsy specimens. Sensitivity and specificity were calculated at varying cut-offs. The optimal threshold was applied to link PRAME expression with the outcome and features of ALM.
Results:
A PRAME staining threshold of 50% (score ≥3) provided the optimum cut-off for differentiating ALM, with a high specificity of 98.3% and sensitivity of 53.3%. Positive PRAME was significantly associated with higher TNM stages (ordinal odds ratio [95% confidence interval], 13.11 [2.55-67.27]) and higher rates of recurrence (hazard ratio, 6.62 [1.42-30.94]) but not with any unfavorable histopathological features or mortality.
Conclusion:
PRAME can be used as an adjunctive diagnostic tool to differentiate malignant from benign acral melanocytic lesions. It may serve as a prognostic marker for poor ALM outcomes.
Insights
PReferentially Expressed Antigen in MElanoma (PRAME) shows promise as a diagnostic marker for acral lentiginous melanoma (ALM). Positive PRAME expression is linked to advanced ALM stages and increased recurrence risk.
Area of Science:
- Dermatopathology
- Oncology
- Immunohistochemistry
Background:
- PReferentially Expressed Antigen in MElanoma (PRAME) is an ancillary tool for cutaneous melanoma diagnosis, including acral lentiginous melanoma (ALM).
- Standardized cut-off values and prognostic performance of PRAME in ALM require further clarification.
Purpose of the Study:
- To assess the diagnostic performance of PRAME immunohistochemistry (IHC) in ALM.
- To explore the prognostic associations of PRAME expression in ALM.
Main Methods:
- Retrospective cohort study of 90 acral melanocytic lesions (60 benign nevi, 30 ALM).
- PRAME IHC performed on biopsy specimens.
- Sensitivity, specificity, and optimal thresholds calculated; PRAME expression linked to ALM outcomes.
Main Results:
- A PRAME staining threshold of 50% (score ≥3) optimized ALM differentiation (specificity 98.3%, sensitivity 53.3%).
- Positive PRAME correlated with higher TNM stages and recurrence rates.
- No significant association found between PRAME and unfavorable histopathological features or mortality.
Conclusions:
- PRAME IHC serves as an effective adjunctive tool for differentiating malignant ALM from benign lesions.
- PRAME expression may indicate a poorer prognosis for ALM patients.