Role of Ki-67 as a prognostic factor in gastrointestinal stromal tumors

Scientific paper - Preliminary note / Short communication

• Author: Borislav Belev
• Author: Iva Brčić
• Author: Juraj Prejac
• Author: Zrna Antunac Golubić
• Author: Damir Vrbanec
• Author: Jadranka Božikov
• Author: Ivan Alerić
• Author: Marko Boban
• Author: Jasminka Jakić Razumović
• Author's institution: University of Zagreb; School of Medicine
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences

Abstract (english)

AIM:

To investigate primarily the prognostic value of Ki-67, as well as other parameters, in gastrointestinal stromal tumors (GISTs). ----- METHODS:

Ki-67, c-KIT, platelet-derived growth factor receptor-alpha (PDGFRα), smooth muscle actin (SMA), CD34, S100 were stained for immunohistochemistry which was performed on formalin-fixed, paraffin-embeded sections on representative block from each case. Proliferation index counted by Ki-67 antibody was calculated as a number of positive nuclear reaction over 100 cells. Immunoreactivity for c-KIT and PDGFRα was evaluated semiquantitatively (weak, intermediate, strong) and for c-KIT type of reactivity was analyzed (cytoplasmic, membrane and "dot-like" staining). Immunoreactivity for SMA, CD34 and S100 were was evaluated as positive or negative antigen expression. Pathologic parameters investigated in this study included tumor size, cell type (pure spindle, pured epitheloid mixed spindle and epitheloid), mitotic count, hemorrhage, necrosis, mucosal ulceration. Clinical data included age, gender, primary tumor location and spread of disease. χ² test and Student's t-test were used for comparisons of baseline characteristics. The Cox's proportional hazard model was used for univariable and multivariable analyses. Survival rates were calculated by Kaplan-Meier method and statistical significance was determined by the log-rank test. ----- RESULTS:

According to the stage of disease, there were 36 patients with localized disease, 29 patients with initially localized disease but with its recurrence in the period of follow up, and finally, 35 patients had metastatic disease from the very beginning of disease. Tumor originated most commonly in the stomach (41%), small intestine was the second most common location (36%). The mean size of primary tumors was 6.5 cm. The mean duration of follow-up was 60 mo. Multiple parameters were analyzed for their effect on overall survival, but no one reached statistical significance (P = 0.06). Analysis of time to progression/relapse in initially localized disease (univariate analysis), tumor size, mitotic count, Ki-67 and type of d-KIT distribution (cytoplasmic vs membrane/"dot-like") showed statistically significant correlation. In multivariate analysis in the group of patients with localized disease, there were only 2 parameters that have impact on relapse, Ki-67 and SMA (P < 0.0001 and P < 0.034, respectively). Furthermore, Ki-67 was analyzed in localized disease vs localized with recurrence and metastatic disease. It was shown that there is a strict difference between these 2 groups of patients (median value was 2.5 for localized disease vs 10.0 for recurrent/metastatic disease, P < 0.0001). It was also shown that the cut-off value which is still statistically significant in terms of relapse on the level of 6%. The curves for survival on that cut-off level are significantly different (P < 0.04, Cox F). ----- CONCLUSION:

Ki-67 presents a significant prognostic factor for GIST recurrence which could be of great importance in evaluating malignant potential of disease.

• Keywords (english): Biopsy; Chi-Square Distribution; Female; Gastrointestinal Neoplasms / chemistry; Gastrointestinal Neoplasms / mortality; Gastrointestinal Neoplasms / pathology; Gastrointestinal Neoplasms / therapy; Gastrointestinal Stromal Tumors / chemistry; Gastrointestinal Stromal Tumors / mortality; Gastrointestinal Stromal Tumors / secondary; Gastrointestinal Stromal Tumors / therapy; Humans; Immunohistochemistry; Kaplan-Meier Estimate; Ki-67 Antigen / analysis; Male; Middle Aged; Multivariate Analysis; Neoplasm Recurrence, Local; Neoplasm Staging; Predictive Value of Tests; Prognosis; Proportional Hazards Models; Risk Factors; Survival Rate; Time Factors; Tumor Burden
• Language: english
• Publication type: Scientific paper - Preliminary note / Short communication
• Publication status: Published
• Peer review: Peer review
• Publication version: Published version
• Journal title: World Journal of Gastroenterology
• Numbering: vol. 19, no. 4, pp. 523-527
• p-ISSN: 1007-9327
• DOI: https://doi.org/10.3748/wjg.v19.i4.523
• URN:NBN: urn:nbn:hr:105:889089
• Publication: 2013-01-28
• Document URL: https://doi.org/10.3748/wjg.v19.i4.523
• Type of resource: Text
• Access conditions: Open access
• Created on: 2024-03-27 19:53:05