PATHOLOGY LABORATORY
Pathology; It is the field of clinical medicine, which consists of the words pathos (disease) and logos (science) and is among the surgical medical sciences in which diseases are examined with scientific methods.
Surgical Pathology
The diagnostic procedures of surgical pathology involve a wide variety of techniques. The most basic technique is at the macroscopic level, and viewing the sample with the naked eye alone can provide the pathologist with sufficient information to make a diagnosis. However, most often the pathologist also performs microscopic examination for an adequate diagnosis and prognosis. Therefore, the microscope is one of the primary tools a pathologist uses. Surgical pathology does not rely only on the eye and the microscope. Almost every stage of pathology studies requires manual labor. The devices are used at certain preparatory stages. Afterward, a good technician completes all the preparations. Physicians and technicians should work together and in harmony in pathology laboratories. For this reason, details such as preparation of a preparation, where to take the section, how to fix it, how the dye is, and how thin the section will be taken are very important in the success of the diagnosis. This shows how important experience and experience are besides knowledge.
Genetics and Pathology
In today's world, pathology and genetics are like two married branches. Especially in cancer studies and in the investigation of somatic mutations, the two branches work together. When the tissue comes to the laboratory, macroscopy studies are performed in the pathology unit. According to the type of cancer, where and how many sections will be taken and how the study will be done are determined. Regardless of which study is performed on the tissue, in the first step, it is necessary to determine which region of the incoming tissue is cancer tissue. It is determined how much of the cancer tissue covers the entire tissue in the area to be examined. After this preliminary study, detailed studies are started for whichever method the study will be carried out. If sequence analysis is required, tissue is taken from the marked region, DNA isolation is performed and the study is started for which gene to be studied. If FISH is to be performed, sections of appropriate thickness are taken for the FISH study. In these sections, the cancerous area is marked and the study is performed by dripping a probe into this area.
Intergen is one of the few laboratories that have both pathology and genetics laboratories. It is a center that turns the collaborative culture into an advantage in favor of the patient. Clinical information is obtained for the incoming samples, the pathology genetic joint council is made and the most accurate tests are determined for the patient.
Likewise, pathology and genetics should work together in “fetal pathology” studies. Genetics and pathology should also work together when it is desired to diagnose a fetus that was evacuated due to an anomaly detected in fetal ultrasonography or that has died in the intrauterine period. With the dysmorphic findings, prenatal findings, ultrasound findings, obstetric history, and family information obtained from the family, the geneticist determines a preliminary diagnosis and gives detailed information to the pathologist. The pathologist learns the important details that should not be overlooked. In light of this information, the pathologist performs an autopsy. The placenta is very important at this stage. Sometimes the diagnosis can only be made by examining the placenta. For this reason, when this study is requested, information should be obtained from our center about how the sample will be sent and how it will be preserved, and it should be ensured that such a valuable tissue is worked under the best conditions. These studies are very important for future pregnancies in the family and to determine if anyone else in the family is at risk.
Intergen is one of the few centers that have both pathology and genetics laboratories. It is a center that turns the collaborative culture into an advantage in favor of the patient. Clinical information is obtained for the incoming samples and the most accurate tests are determined for the patient after the work of the pathology genetic joint council.
Likewise, pathology and genetics should work together in “fetal pathology” studies. Genetics and pathology should also work together when the diagnosis should be made on a fetus that was evacuated due to an anomaly detected in fetal ultrasonography or that has died in the intrauterine period. With the dysmorphic, prenatal, and ultrasound findings, obstetric history, and family information obtained from the family, the geneticist determines a preliminary diagnosis and gives detailed information to the pathologist. The pathologist learns the important details that should not be overlooked. In light of this information, the pathologist performs an autopsy. The placenta is very important at this stage. Sometimes the diagnosis can only be made by examining the placenta. For this reason, when this study is requested, information should be obtained from our center about how the sample will be sent and how it will be preserved, and it should be ensured that such a valuable tissue is worked under the best conditions. These studies are very important for future pregnancies in the family and to determine if anyone else in the family is at risk.
Biopsy
A small piece of tissue taken from organs that can be accessed in the body is called a biopsy sample. Examples of these are parts taken from moles on the skin, gastrointestinal samples taken endoscopically, lung tissue samples taken by bronchoscopy, and bladder samples taken cystoscopically. These samples are subjected to special staining and examined through a microscope which provides valuable information about the presence of the disease. It is a preliminary diagnosis method for a larger surgical intervention when necessary.
Resection
Removal of part or all of the diseased organ is called resection, which is complete removal. The removed part is delivered to our laboratory in protective liquids. Our experts examine the part, take the necessary samples and place them in a special tracking machine for further detection. The ready-made pieces are then cut as thin as onion skin and painted. Now, under the microscope, our pathologists are ready to examine the cells. Sometimes special staining methods may be required to diagnose the examined tissue. Diagnostic success increases when these staining methods are used. In addition, for the use of some treatments, it is important to carry out these dyeings and the results beforehand.
What is cytopathology?
Cytology means the science of cells. The first changes in diseases begin in the cell, the smallest living block structures of the human body. It then spreads and reveals the disease picture. Cytopathology is one of the sub-branches of pathology that examines samples taken from tissues and body fluids to determine changes in cells in the diagnosis of diseases.
Different cells or cancer cells are searched in various fluids obtained from the body, in swabs taken from the cervix and vagina, and in thyroid, breast, liver, and bone marrow needle aspiration materials.
Cervicovaginal Smear Test
Pap smear in the screening of cervical cancer has been performed around the world for about 100 years and is a proven test. Smear tests are reported in approximately 24-72 hours. Unlike conventional smears, if liquid-based smear preparations contain suspicious dysplastic cells in the routine examination, an HPV PCR test, a molecular test, is required for the type determination of the causative HPV (Human Papilloma Virus). If the sample is taken following the liquid-based method when taking the sample for the first time, HPV studies can also be planned without taking samples from the patient again. It should not be forgotten that cervical cancer is curable cancer when detected early. Screenings are very important.
Fine Needle Aspiration Biopsies
Fine-needle aspiration biopsy (FNAB), which enables the analysis of living tissue samples and the diagnosis of diseases quickly and easily, is most commonly used in the diagnosis of thyroid nodules, salivary gland masses, lymph nodes, and lung nodules. Fine needle aspiration biopsy, which is a painless, comfortable, and reliable diagnostic method, provides significant advantages to both the physician and the patient. If the results are as desired after the procedure, the patient can get rid of unnecessary surgical procedures and anesthesia. The risks of fine-needle aspiration biopsy, which can be performed safely during pregnancy, such as cancer spreading or cell transplantation, have been shown very rarely in studies.
Cytology in Body Fluids
It covers exfoliative cytology studies in body fluids (such as saliva, cerebrospinal fluid, urine, bronchioalveolar lavage, effusions, pleural, intra-abdominal, and intra-articular).
Immunohistochemistry (IHC)
Immunohistochemistry is a technique to search for a specific antigen (protein) or cell in a cell or tissue. In our pathology laboratory, immunohistochemical reactions are applied in different situations. The most important applications are Histogenetic diagnosis of tumor cells, determination of tumor subtypes (for example, lymphoma), characterization of the first site of malignant tumor, investigation of therapeutic signs and prognostic factors in some diseases, differentiation of benign and malignant tumors, understanding of structures and material secreted by the cell. Advanced immunohistochemical staining studies are performed on the samples coming to our center.
Immunotherapy
Immunotherapy is a type of treatment that uses to stimulate or suppress the immune system to help the body fight cancer, infection, and other diseases. Some types of immunotherapy target only certain cells of the immune system and some affect the immune system in a general way. Types of immunotherapy include cytokines, vaccines, Basil Calmette-Guerin (BCG), and some monoclonal antibodies.
What is PD-L1?
PD-L1 is a cell membrane protein that prevents the immune system from recognizing the body's cells as foreign, known as a programmed death ligand. However, this important mechanism can turn into a disadvantage when it comes to cancer since tumor cells are also the metamorphosis of our cells. PD-L1 is a molecule that suppresses the activation of T cells of the immune system and causes the progression of tumors.
What does PD-L1 positive mean?
Some tumors have high levels of PD-L1 protein on their cell surface and these are called PD-L1 positive tumors. PD-L1 is a very valuable marker predicting the efficacy of anti-PD-1 and anti-PD-L1 class immunotherapies. FDA-approved anti-PD-1 immunotherapies including pembrolizumab, nivolumab, cemiplimab, atezolizumab, durvalumab, and avelumab. The number of approved active substances is increasing day by day. The important thing here is to determine well who the drug will work for and who will not.
Studies show that PD-L1 levels in tumor cells can be a guide in the selection of treatment (immunotherapy).
Depending on the type of tumor and the organ of origin, PD-L1 positive patients respond to immunotherapy drugs at a rate 2-3 times higher than negative patients.
Biopsy samples taken from tumors are prepared as paraffin block sections in the pathology laboratory. It is evaluated by immunohistochemical staining technique specific to PD-L1. The tissue sample must contain a minimum of 100 tumor cells for examination. When all conditions are met;
• Less than 1% or no staining of the tumor indicates the negativity of PD-L1. In this case, the use of immunotherapy in the treatment of cancer will either have no or little effect.
• If there is cell membrane staining between 1% and 49% in the tumor, this indicates PD-L1 positivity and the cancer patient can receive immunotherapy together with other treatments. Immunotherapy will have a positive effect on the patient's clinic.
• If PD-L1 staining more than 50% in the tumor is an indicator of high PD-L1 positivity, immunotherapy can be considered the first step in the treatment of cancer. Other treatments can then be started.