|
|
Use of Imunohistochemical Methods in Diagnostics of Neoplasms
VELKOVÁ, Michala
This thesis deals with the application of immunohistochemical methods in the diagnosis of neoplasms. Indications of immunohistochemical methods of particular departments in Hospital Písek, a.s. are outlined there. It describes the origins and development of this method in the Pathological Anatomy Department, Hospital Písek, a.s. In the theoretical part, I describe knowledge of single methods. As for immunohistochemistry, I focused on the determination of antigens and the use of suitable primary antibodies for diagnosing diseases, mostly neoplasms. There are 20 primary antibodies available at the Department of Pathological Anatomy. In the practical part, I compare conventional staining and immunohistochemical methods with conventional staining and special staining methods in histology for the diagnosis of tumours. Hematoxylin eosin serves for distinguishing of essential cellular components. Selective staining enables colour differentiation of various tissue components. Using immunohistochemistry, the presence of certain tissue antigens by antibody reaction with the immobilized chemical compounds is detected. This comparison I was applied at the differential diagnosis of malignant melanoma and myogenic tumours at the Pathological Anatomy Department, Hospital Písek, a.s. For the determination of malignant melanomas, initially the sample was histologically processed and stained with Hematoxylin eosin staining base. Secondarily, the argentaffin reaction was used to detect melanin pigment and immunohistochemical staining of antigen HMB 45 using a mouse monoclonal antibody against HMB 45 by Dako Company and S 100 protein using a polyclonal rabbit antibody against S 100 by Dako Company. 14 samples of patients with malignant melanoma were examined this way. HMB 45 was stained positively in 12 samples out of 14 in total. Monoclonal antibody against HMB 45 is for malignant melanoma quite specific. S 100 protein was detected in all tissue samples. Polyclonal antibody against S 100 shows higher sensitivity, however it is not very specific. It is more used to distinguish neuroectodermal and nonneuroektodermálních lesions. Melanin was detected in 11 tissue samples. Detection of melanin is also non-specific and complicated. Argentaffin reaction shows colouring of other substances contained in the cytoplasm, such as lipofuscin therefore it is necessary to use other methods for the melanoma diagnosis, e.g. immunohistochemistry. In the diagnosis of myogenic neoplasms, Hematoxylin eosin basic staining was used and subsequently immunohistochemical examination followed to detect smooth muscle actin and desmin using monoclonal mouse antibodies by Dako Company and transparent Hematoxylin van Gieson staining, which is used less than in the past. A total of 94 myogenic neoplasms (leiomyoms uterus) were examined. 72 neoplasms stained with Hematoxylin van Gieson showed a positive colour reaction of muscle mass and 22 neoplasms weak colour reaction. Smooth muscle actin and Desmin was detected by immunohistochemistry in 92 samples. The main problem of Hematoxylin van Gieson staining remains less specificity and sometimes ambiguous differentiability of colour tones in their own preparation impeding and preventing to set a reliable diagnosis in some cases. For this reason, immunohistochemical detection of Smooth muscle actin and Desmin (amongst others) is preferred as key parameters. Preferably, you can then use positive antibody reaction with Smooth muscle actinof myoepiteliels in the search for possible invasiveness mainly to differentiate in situ and microinvasive tumous in glandular organs. The differential diagnosis of myogenic origin tumours currently prefers immunohistochemical methods to special staining for high sensitivity and specificity, as well as in the differential diagnosis of malignant melanoma. When combined, both approaches complement each other well and provide relatively high degree of certainty in determining cells origin.
|
guest ::
RSS feed.