For these molecular diagnostic tests we use the genetic material, the DNA of the tumor cells. In most cases DNA is extracted from tissue samples taken from the body of the patient for pathology diagnostic tests. These samples are stored for 20-30 years on average by the pathology department of hospitals, so in most cases, they are readily available. We have developed our molecular diagnostic technology so that both tissue samples fixed in formalin and cytology smears are suitable for testing. Thus, there is usually no need for repeated sampling.
Of course, it may happen that a tumor tissue sample is destroyed during earlier tests or is too small. Furthermore, repeated sampling may be necessary from a recurrent or metastatic tumor because the biological properties of the tumor may change, even if only to a limited extent.
We test the genetic material extracted from the sample to determine whether or not genes contain abnormal changes. In order to detect these gene mutations, the small DNA sample should be processed, that is, multiplied. We use a state-of-the-art technology for multiplying DNA-sequences, the so-called laser catapult microdissection. The method implies introducing the tumors cells, marked with the microscope, into the reaction tube using a laser beam, so that subsequently only the DNA from the tumor is tested. This technology allows achieving the highest accuracy in testing the DNA from the tumor cells. Another advantage is that the DNA necessary for the test may be obtained from really small tissue samples.