Background: Loss of cyclin-dependent kinase (CDK) 10 expression may be an important mechanism of tamoxifen resistance and the 5' CpG island associated with the CDK10 gene has been suggested to be a target for aberrant methylation in breast cancer.
Patients and methods: The methylation status of CDK10, RASSF1A (Ras association domain family 1A) and DAL-1 (differentially expressed in adenocarcinoma of the lung) was determined by means of methylation-specific PCR (MSP) in the formalin-fixed, paraffin-embedded (FFPE) surgical specimens of 96 breast carcinoma patients. Reverse transcription kinetic PCR (RT-kPCR) was used for assessment of the expression of CDK10.
Results: The unmethylated form of CDK10, RASSF1A and DAL-1 was detected in all the samples analyzed. Methylation of the CDK10 5' region was not found in any of the 96 breast cancer samples. RASSF1A methylation was detected in 75 out of 96 (78%) and DAL-1 in 9 out of 15 (60%) breast cancer samples, respectively. Consistent with the methylation results, the expression of CDK10 was detected in all 96 samples.
Conclusion: CDK10 is not a target for aberrant DNA methylation in breast cancer.