Melanoma inhibitor of apoptosis protein is expressed differentially in melanoma and melanocytic naevus, but similarly in primary and metastatic melanomas
- Pathology Department, West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, China
- Correspondence to: Dr Q Zhou Pathology Department, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China;
- Accepted 2 March 2005
Background: Malignant melanoma is highly resistant to current treatments. The inhibitor of apoptosis protein (IAP) family member, melanoma IAP (ML-IAP), is overexpressed in some melanoma cell lines, rendering them resistant to apoptotic signals. Targeting ML-IAP is a promising approach to treating melanoma. However, the status of ML-IAP expression in human melanoma tissues and the difference in expression between melanoma and melanocytic naevus are not known.
Aims: To investigate these issues.
Methods: ML-IAP expression in 48 archived patient samples (34 melanomas and 14 dermal naevi) was assessed by immunohistochemistry and by in situ hybridisation and reverse transcription polymerase chain reaction (RT-PCR) assays developed for the study.
Results: Expression of ML-IAP was detected in 47.6–70.6% (10 of 21 to 24 of 34) of the melanomas, varying with detection methods. The expression rate in melanoma was much higher than that in melanocytic naevus (10.0–21.4%; one of 10 to three of 14). No significant difference was seen between primary and secondary melanomas. ML-IAP expression rates assessed by the three methods were in agreement.
Conclusions: The ML-IAP expression rate in archived melanoma tissues is around 50–70%, with no difference between primary and secondary melanomas. A small number of dermal naevi (∼ 20%) also expressed ML-IAP.
- BIR, baculoviral inhibitory repeat
- DIG, digoxigenin
- ML-IAP, melanoma inhibitor of apoptosis protein
- RT-PCR, reverse transcription polymerase chain reaction
- SMAC, second mitochondrial activator of caspases
- SSC, saline sodium citrate