Hipoteza istraživanja bila je da je serumska razina IL-6 i ekspresija IL-6 u tkivu prostate viša kod bolesnika s karcinomom prostate nego kod bolesnika s PIN-om, BPH i prostatitisom. Istraživanje se temeljilo na analizi serumske razine IL-6 i IL-6 ekspresije u uzorcima tkiva dobivenim biopsijom prostate od 148 bolesnika (82 bolesnika s karcinomom prostate, 25 bolesnika s BPH i 24 s PIN-om i 17 s prostatitisom). Razina IL-6 u serumu bolesnika određivana je elektrokemiluminiscentnim imunotestom (ECLIA), a za određivanje ekspresije IL-6 u uzorcima tkiva prostate korištena su mišja antihumana IL-6 antitijela (NCL-L-IL-6). Razina IL-6 u serumu bila je značajno viša kod bolesnika sa slabo diferenciranim karcinomom prostate u odnosu na bolesnike sa srednje diferenciranim karcinomom prostate (p = 0,007). Također, povišene su razine IL-6 u serumu nađene kod bolesnika s metastazama u kostima. Serumska razina IL-6 bila je povezana s patološkim stupnjem bolesti (GS), ali ne i s ekstraprostatičnom proširenošću bolesti. IHC bojenjem nađena je ekspresija IL-6 u citoplazmi normalnih epitelnih stanica, premalignih i malignih stanica prostate te u stromalnim stanicama prostate (mononukleari, fibroblasti i endotelne stanice). Najveća ekspresija IL-6 u normalnim sekretornim stanicama nađena je u uzorcima tkiva s BPH (60% uzorka imalo je ekspresiju IL-6 u više od 50% normalnih sekretornih stanica), koja je postupno opadala u PIN-u, zatim prostatitisu. Najmanja ekspresija IL-6 nađena je u uzorcima tkiva s karcinomom prostate. Također je nađeno da su u bazalnim stanicama najveću ekspresiju IL-6 imali uzorci tkiva s BPH (52% uzoraka s BPH imalo je u više od 50% bazalnih stanica ekspresiju IL-6), a najmanju ekspresiju IL-6 u bazalnim stanicama imali su uzorci s karcinomom prostate. Ekspresija IL-6 bila je veća u epitelnim stanicama nego u stromalnim. Epitelne maligne stanicame imale su veću ekspresija IL-6 nego okolne normalne epitelne stanice. Nije nađena značajna razlika u ekspresiji IL-6 u premalignim i malignim epitelnim stanicama (p = 0,814). Proinflamatorni citokin IL-6 ima važnu ulogu u razvoju i progresiji adenokarcinoma prostate i mogao bi biti cilj za imunoterapiju.

The hypothesis of the research was that the serum IL-6 level and IL-6 expression in the prostate tissue are higher in patients with prostate cancer in comparison to patients with prostatic intraepithelial neoplasia (PIN), benign prostatic hyperplasia (BPH) and prostatitis . The research was based on the analysis of serum IL-6 levels and IL-6 expression in tissue samples obtained from prostate biopsy from 148 patients (82 patients with prostate cancer, 25 patients with BPH, 24 patients with PIN and 17 patients with prostatitis). Serum IL-6 levels were measured by electrochemiluminescence immunoassay (ECLIA) and IL-6 expression in the prostate tissue samples was determined by mouse anti human IL-6 antibodies (NCL-L-IL-6). Serum IL-6 levels were significantly higher in patients with poorly differentiated prostate cancer in comparison to patients with moderately differentiated prostate cancer (p = 0.007). Also, high serum IL-6 levels were found in patients with bone metastases. Serum IL-6 levels were associated with Gleason score (GS), but not with extraprostatic extension. Immunohistochemical (IHC) staining identified IL-6 expression in cytoplasm of the normal epithelial cells, premalignant and malignant prostate cells and in stromal prostate cells (mononuclear, fibroflasts and endothelial cells). The highest IL-6 expression in normal secretory cells was found in prostate tissue samples with BPH (60% of the samples had IL-6 expression in more than 50% normal secretory cells), IL-6 expression decreased in PIN and prostatitis. The lowest IL-6 expression in normal secretory cells was found in the tissue samples with prostate cancer. Moreover, basal cells had the highest IL-6 expression in the tissue samples with BPH (52% of the BPH tissue samples had in more than 50% basal cells IL-6 expression) whereas the lowest IL-6 expression in basal cells was found in the tissue samples with prostate cancer. IL-6 expression was higher in epithelial cells than in stromal cells. Epithelial malignant cells showed higher IL-6 expression than normal epithelial cells. There was no significant difference in IL-6 expression in premalignant and malignant epithelial cells (p = 0.814). Proinflammatory cytokine IL-6 has an important role in the development and progression of prostate adenocarcinoma and could be an effective target for immunotherapy.