Am J Cancer Res 2013;3(4):411-423

Original Article
Ki67-BCL2 index in prognosis of malignant peritoneal mesothelioma

Krishna Pillai, Mohammad H Pourgholami, Terence C Chua, David L Morris

Department of Surgery, St. George Hospital, University of New South Wales, Kogarah, NSW 2217, Australia

Received July 17, 2013; Accepted July 27, 2013; Epub August 14, 2013; Published August 30, 2013

Abstract: Background: malignant peritoneal mesothelioma (MPM) is a rare peritoneal mesothelial neoplasm. Ki67 and BCL2
are established prognostic markers in several cancers. High Ki67 expression indicates tumour progression, whilst similar
expression of BCL2 retards tumour replication. Traditionally, prognosis in MPM is gauged with a single biomarker assessed
separately in a dichotomous manner. Here, we examine prognosis with dual biomarkers incorporated in a model to predict
survival. Materials and methods: Forty two MPM archival patient tumours were screened for Ki67 and BCL2 by
immunohistochemistry and evaluated using standard methods. Ki67 and BCL2 expression was incorporated into a prognostic
model to develop Ki67-BCL2 index. Using this index, three hazard groups were identified (high, medium and low risk). Kaplan-
Meier survival analysis was performed to assess the significance of these hazard groups in the various clinicopathological
categories. Results: In all clinicopathological categories, high risk group showed poor prognosis compared to low risk group (p
= < 0.001). Compared to medium risk, high risk group carried poor prognosis in all tumours, females, epitheloid tumours,
peritoneal cancer index (PCI) < 20, ≥ 20, age at diagnosis (AAD) < 60, and ≥ 60 years. Independent of the Ki67-BCL2 index,
male, sarcomatoid, PCI ≥ 20 and AAD ≥ 60 were poor prognostic factors. High risk group was an independent poor prognostic
factor in all tumours, males, females and age < 60 years. The distribution of high risk: low risk group in male and female was 3:
2 and 2: 3, respectively, indicating a gender difference. Comparing hazard ratios generated by Ki67-BCL2 index to that of either
Ki67 or BCL2, as a single prognostic biomarker, there was a reduction of HR values. Conclusion: Ki67-BCL2 index seems to
suggest a more sensitive method of predicting prognosis. However, the current model needs further evaluation in an
independent large cohort sample. (ajcr0000218).

Keywords: Ki67, BCl2, prognosis, malignant peritoneal mesothelima

Address correspondence to: Dr. Krishna Pillai, Department of Surgery, St George Hospital, University of New South Wales,
Kogarah, NSW 2217, Australia. Tel: + 612 – 9112070; Fax: + 612 – 91133997; E-mail: z3179288@unsw.edu.au
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American Journal of Cancer Research
ISSN: 2156-6976