Diagnosis, prognosis and therapeutic control of malignant diseases using PLA2R1 methylation analysis
In addition to coronary heart diseases cancer is the leading cause of death worldwide accounting for 7.6 million deaths every year. The number of individuals diagnosed with cancer increases each year due to aging of the population. New statistics show that one in three women and one in two men will develop cancer in their lifetime. To improve the prognosis of malignant disorders new biomarkers are needed with high diagnostic sensitivities and specificities, which allow an early and specific diagnosis of cancer. In addition, control methods are needed to monitor the efficiency of newly developed strategies to treat high-risk myelodysplastic syndrome (MDS) and acute myeloidleukemia (AML) patients with DNA methyltransferase (DNMT) inhibitors such asazacitidine (Vidaza) or decitabine (Dacogen). Finally, sensitive methods are necessary to analyse minimal residual diseases (MRD) to improve the efficiency of treatments.
On the basis of distinct methylated regions of the PLA2R1 gene in cancers, test kits can be developed using these regions as biomarker in the diagnosis of malignant diseases. By using this method for example leukemia can be diagnosed in comparison to healthy individuals. Furthermore, minor malignant cell fractions can be identified in peripheral blood samples as shown, for example in a patient with AML, FAB M2, afterallogenic hematopoietic stem cell transplantation during azacitidine treatment.The degree of methylated PLA2R1 can also be used to control the therapy efficiency of high-risk MDS and AML patients using azacitidine (Vidaza). Alternatively to the commonly used bisulfite-methods free DNA from serum, plasma or urine can be screened for the occurrence of circulating methylated PLA2R1 fragments using methylation-specific restriction enzymes for example in leukemia or prostate cancers.
Two test systems were established. One is based on bisulfite-modified genomic DNA using specific oligonucleotides and methylation calibrators in a real-time PCR-HRM analysis. The second test system is more simple using free DNA and digestion by distinct methylation-specific restriction enzymes and specially designed oligonucleotides followed by real-time PCR and agarose gel electrophoresis as control. The latter test system only needs 200-500 μl of serum or plasma. In addition, urine samples after digital rectal exam or seminal plasma in case of prostate cancers, cerebrospinal fluids in case of brain diseases, nipple aspirates in case of mammary cancers, stool samples in case of colon carcinoma, or bronchoalveolar lavage in case of lung cancers can be easily analysed in respect to the presence of malignant cells.
- Diagnosis, prognosis and therapeutic controls of malignant diseases (leukemia, multiple myeloma, solid tumors such as prostate cancers, melanoma, mammary cancers, etc.)
- Differentiation between benign hyperplasia of prostate (BPH) and prostate cancers in patients with serum PSA values between 3.0 and 10.0 ng/ml. By this way the frequency of performing prostate biopsies can be significantly reduced.
- Risk stratification of MDS patients to develop AMLA better therapeutic control of high-risk MDS and AML patients treated with DNMT inhibitors such asazacitidine (Vidaza) or decitabine (Dacogen).
- Analysis of minimal residual diseases (MRD) using PLA2R1 test kits improving the efficiency of therapies.
- Screening of natural products reducing gene