Role of Ki 67 Labelling Index as an Adjunct to Histopathological Diagnosis for Grading of CNS Tumours

The Central Nervous System tumours are unique as they arise from specialized tissue. CNS tumours constitute a wide range of neoplasm that differs in their location, age distribution, extent of invasiveness, morphological features and tendency for progression. We wanted to evaluate the traditional morphological data with knowledge on the prognostication marker Ki 67 antibody in evaluating tumour grade and prognosis of CNS neoplasm.METHODSThis is a cross section study carried out between March 2015 and September 2016 in histopathology department of Dhiraj Hospital on 50 cases of CNS tumours. Immunolabelling of all biopsies was done by horse radish peroxidase technique using rabbit monoclonal antibody to Ki 67 (clone SP 6) (Thermo Scientific, USA). Ki 67 immune positive labelling index was obtained for each tumour and correlated with mitotic labelling index obtained by conventional morphological grading as per WHO 2007 classification.RESULTSIn our study of CNS tumours, all age groups were studied. The mean Ki 67 labelling index (LI) values +/-SD for WHO Grade I tumours were- meningiomas (10) 3.85 (+/1.97) %, schwannoma (3) -3.0 (+/-2.97) %, pituitary adenoma (1) 0.6, craniopharyngioma (1) -1.1% and ependymoma (6) 2.62 (+/-0.60) %. WHO Grade II tumours- atypical angiomatous meningioma (1) -2%, atypical mucinous meningioma (2) -6.15 (+/-1.06) %, gemistocytic astrocytoma (1) -12; pleomorphic xanthoastrocytoma (2) -4.3 (+/-0.99) %, astrocytoma grade ii (2) -3.3 (+/-0.71) %, oligodendroglioma grade ii (4) - 3.9 (+/-0.88) %. WHO grade III tumours- anaplastic astrocytomas (5) -6.82 (+/-2.17) %, anaplastic oligoastrocytoma grade iii (1) -10.8 %. who grade iv-glioblastomas (7) -18.44 (+/-3.97) %; medulloblastomas (1) 20%, metastatic tumour (3) -36 (+/- 22.16) %. In our study, the mean Ki 67 LI (± SD) values for grade II, III and IV glioma is as follows: 4.76 (+/-2.83) %, 7.48 (+/-2.53) % and 18.44 (3.97) % respectively.CONCLUSIONSThis study shows that Ki 67 LI serves as an essential clinical prognostic proliferation marker of particular importance in cases with lower grade histology of Grade II & Grade III astrocytomas, Grade II & Grade III oligodendrogliomas. Ki 67 LI is important in determining benign, atypical and malignant meningiomas, non-invasive and invasive pituitary adenomas.

Frequency of Ki-67 (MIB-1) and P53 expressions among patients with prostate cancer.

Context: Prostate cancer is the most common malignant tumor in men. Tumor grade is one of the most important prognostic factors of prostate cancer. P53 and Ki-67 expressions have also been considered to be prognostic factors. Aims: This study was performed to investigate the frequency of these proteins expression and compare the obtained results with Gleason's grading. Settings and Design: In this cross-sectional study, 49 paraffin blocks of prostate cancers were assessed. Tumor grade was determined according to the Gleason's criteria. Materials and Methods: Ki-67 and P53 expressions were determined by immunohistochemical staining. Statistical Analysis: The obtained results were analyzed and evaluated using Spearman's statistical test (SPSS version 15). Results: Three out of 49 (6.1%) cases were well differentiated, 21 (43%) moderately differentiated and 25 (51%) were poorly differentiated. P53 was negative in all well-differentiated cases. Ki-67 was negative in 14 cases (28%) including all well-differentiated tumors. Among moderately and poorly differentiated tumors Ki-67 was negative in eight (38%) and three (12%) of cases, respectively. A statistically significant relation was observed between the increased Ki-67 labeling index (LI) and increased Gleason's grade. Conversely, no statistically significant relation was found between P53 expression and increased Gleason's grade. Conclusions: According to the findings of this study, it seems that Ki-67 can be used as a prognostic factor for prostate cancer. On the other hand, the probable relation between P-53 and prostate cancer prognosis requires further studies.

Expression of Ki-67/MIB-1 in Bone Marrow Biopsies from Patients with Myelodysplastic Syndromes and Aplastic Anemia / 대한임상병리학회지

BACKGROUND: Sometimes myelodysplastic syndrome (MDS) is especially difficult to distinguish from acquired aplastic anemia (AA) because of the clinical, cytologic, and histologic similarities of these two disorders. The proliferative activity of the hematopoietic cells is very different in various hematologic disorders and Ki-67 expression in the bone marrow cells is an useful cell proliferation marker. We tried to evaluate the significance of Ki-67/MIB-1 immunoreactivity in the discrimination of MDS and AA. METHODS: Bone marrow biopsy specimens from 56 individuals, 7 controls, 21 with MDS, 16 with AA and 12 with acute leukemia were obtained in Pusan Paik Hospital. Immunohistochemial staining for Ki-67 antigen was assessed by the MIB-1 monoclonal antibody using a microwave oven-based antigen retrieval technique. RESULTS: The mean values (+/-SD) of Ki-67 positive cells was as follows: control group, 16.8+/-3.6%; MDS, 25.3+/-10.1%; AA, 5.1+/-2.9%; acute leukemia, 30.5+/-10.4%. MDS cases showed statistically higher values of Ki-67 than did those of AA cases and control group (P<0.001) but no significance in Ki-67 frequencies was observed between the cases of MDS and acute leukemia. CONCLUSIONS: In the bone marrows of MDS cases the Ki-67 positive cells were frequently observed, suggesting high proliferative activity even in the nonleukemic state, while most of the bone marrows in AA showed very low proliferative activity. Thus immunohistochemical staining with Ki-67/MIB-1 would be useful in the discrimination of AA and MDS by the difference of Ki-67 positive cell percentage in the bone marrow.