Abstract
Introduction. Quantitative immunohistochemistry (IHC) plays a key role in understanding the state and degree of malignancy of clear cell renal cell carcinoma (CCRCC) tumors, namely the study of the stability factor Cytokeratin, Pan АЕ1/АЕ3 in the cytoplasm and the proliferative activity factor Ki-67 in nuclei, tumor (TC) and epithelial (EC) cells.
Objective: To reveal the quantitative interrelation between the IHC parameters of Cytokeratin, Pan AE1/AE3 cytoplasmic expression, and the IHC parameters of Ki-67 SP6 nuclear expression in TC and EC in CCRCC grades G1 and G3.
Materials and methods. Quantitative IHC was performed on postoperative material taken from the peripheral and central parts of tumors from 11 patients with CCRCC G1 and G3. The control consisted of biopsies of the renal cortex from macroscopically “clean” surgical margins of the kidney. The material was fixed in a 10% neutral formalin solution, embedded in paraffin, and sectioned into 4 µm slices using a microtome. The sections were placed on glass slides and subjected to IHC staining for Cytokeratin (Pan AE1/AE3 cytoplasm) and Ki-67 (SP6 nuclear) markers of TC and EC using standard protocols. Quantitative assessment of IHC expression (as a percentage) was performed using automated software for mathematical image analysis, including binarization, clustering, and pixel-level image formalization. The results were denoted as the index of stable intermediate filament proteins (IS Cytokeratin, Pan AE1/AE3) for TC and EC, and the labeling index of proliferative nuclei (LI Ki-67 SP6) for TC and EC.
Results. The IS Cytokeratin, Pan AE1/AE3 parameters for TC were higher in the peripheral parts of the tumor nodule in CCRCC G1 compared to its central parts (22.7%>12.8%). Similarly, the IS Cytokeratin and Pan AE1/AE3 parameters for TC were higher in the peripheral parts of CCRCC G3 than in the central parts (10.2% > 3.7%). The control IS Cytokeratin, Pan AE1/AE3 parameters for EC of nephrons from macroscopically “clean” kidney margins were higher in CCRCC G1 than in CCRCC G3 in the same patients (27.0%>25.8%). The LI Ki-67 SP6 parameters for TC were lower in the peripheral parts of CCRCC G1 compared to its central parts (4.63%<11.20%). Likewise, LI Ki-67 SP6 parameters for TC were lower in the peripheral parts of CCRCC G3 compared to its central parts (3.86%<13.22%). The control LI Ki-67 SP6 parameters for EC of nephrons from macroscopically “clean” kidney margins were lower in CCRCC G1 than in CCRCC G3 in the same patients (0.00351%<0.00848%).