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ORIGINAL ARTICLE
Year : 2020  |  Volume : 9  |  Issue : 1  |  Page : 42-45

A quantitative expression of KI-67 to assess the malignant transformation potential in oral leukoplakia and erosive lichen planus


Department of Oral Pathology and Microbiology, SIBAR Institute of Dental Sciences, Tekallapadu, Guntur, Andhra Pradesh, India

Date of Submission11-Jul-2019
Date of Decision26-Oct-2019
Date of Acceptance28-Nov-2019
Date of Web Publication14-May-2020

Correspondence Address:
Dr. Haranath Danda
Department of Oral Pathology and Microbiology, SIBAR Institute of Dental Sciences, Tekallapadu, Guntur - 522 509, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JDRNTRUHS.JDRNTRUHS_77_19

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  Abstract 


Introduction: The basic, living, structural and functional unit of the body is known as a 'Cell'.[1] In both embryonic and post-embryonic existence, cell proliferation plays an important role in the biological process of living organisms.[2] The loss of control in the biological process leads to cancer. Leukoplakia and erosive lichen planus (ELP) are potentially malignant disorders. Ki67 is a protein indicative of cell cycle progression and cell proliferation.
Aim: To evaluate the quantitative expression of Ki-67 in oral leukoplakia (OL) and ELP.
Materials and Methods: Samples were divided into three groups, namely, paraffin-embedded (PE) tissue blocks (10 each) of normal oral mucosa tissue obtained from individuals undergoing third molar surgical removals (Group I); OL (Group II) and ELP (Group III), all of which were confirmed histologically. All the sections were subjected to immunohistochemistry (IHC) using Ki-67, and the number of immunopositive cells was evaluated.
Results: Ki-67 positivity in three groups was observed as 31% in controls, 40% in leukoplakia and 36% in ELP.
Conclusion: Our study revealed more Ki-67 positivity in leukoplakia than ELP, which indicates more malignant transformation potential for Leukoplakia.

Keywords: Erosive lichen planus, Ki-67, leukoplakia


How to cite this article:
Danda H, Pusarla PC, Reddy GS, Kumar KK, Chandra LP, Reddy BV. A quantitative expression of KI-67 to assess the malignant transformation potential in oral leukoplakia and erosive lichen planus. J NTR Univ Health Sci 2020;9:42-5

How to cite this URL:
Danda H, Pusarla PC, Reddy GS, Kumar KK, Chandra LP, Reddy BV. A quantitative expression of KI-67 to assess the malignant transformation potential in oral leukoplakia and erosive lichen planus. J NTR Univ Health Sci [serial online] 2020 [cited 2020 May 30];9:42-5. Available from: http://www.jdrntruhs.org/text.asp?2020/9/1/42/284323




  Introduction Top


The basic, living, structural and functional unit of the body is known as the 'Cell'.[1] In both embryonic and post-embryonic existence, cell proliferation plays an important role in the biological process of living organisms.[2] The loss of control in the biological process leads to cancer. Many studies revealed that abnormal cell proliferation could be a precursor and predictor of tumorigenesis. Potentially malignant disorders were defined by the World Health Organization (WHO) in 2005 as the risk of malignancy being present in a lesion or condition either at time of initial diagnosis or at a future date.[3] The WHO-supported definition in 2005 of oral leukoplakia (OL) was 'A white plaque of questionable risk having excluded (other) known diseases or disorders that carry no increased risk for cancer'.[4] Oral lichen planus (OLP) is a chronic inflammatory T cell-mediated disease, clinically manifested as white, lacy plaques, located mainly on the buccal mucosa and tongue.[5] The WHO differentiated OLP into the group of potentially malignant disorders, its most severe complication is the progression into oral squamous cell carcinoma (OSCC).[1] Ki-67 is a proliferation marker to measure the growth fraction of cells in pre-malignant and malignant lesions, along with normal tissues. It is a nuclear protein associated with cell proliferation and maximally expressed in cells with Gap 2 (G2) and mitotic (M) phases of the cell cycle but absent in resting cells.[5]

Aim of the study

The aim of this study was to investigate the quantitative expression of Ki-67 in OL and erosive lichen planus (ELP).


  Materials and Methods Top


Source of data

The present study was carried out using 10 formalin-fixed paraffin-embedded (FFPE) tissue blocks of each group, diagnosed histologically as OL and ELP, which were retrieved from the archives of Department of Oral Pathology and Microbiology, SIBAR Institute of Dental Sciences, Guntur. As controls, 10 FFPE tissue blocks of normal oral mucosa over the impacted third molars were taken from the patients undergoing surgery for impactions after approval from the Institutional Ethics Committee, SIBAR Institute of Dental Sciences. The study consisted of 30 samples categorised into three groups:

  • Group I- Controls (10)
  • Group II- OL (10)
  • Group III- ELP (10)


The inclusion criteria of the control group comprised of apparently normal, healthy oral mucosa without any clinical lesions. The exclusion criteria comprised of subjects having the habit of smoking and alcohol. Any lesions other than OL and ELP were excluded. The methodology included serial sections of 4 μm thickness obtained from the archival material. The sections of Group I, II and III were first subjected to routine haematoxylin and eosin examination to reconfirm the diagnosis. Later, other sections of all the three groups were subjected for immunohistochemical analysis using anti-Ki-67 antibody. [Controls- [Figure 1] OL- [Figure 2], ELP- [Figure 3]
Figure 1: 20× view of a photomicrograph of normal oral mucosa showing Ki-67 immunopositivity

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Figure 2: 20× view of a photomicrograph of oral leukoplakia showing Ki-67 immunopositivity

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Figure 3: 20× view of a photomicrograph of erosive lichen planus showing Ki-67 immunopositivity

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Interpretation

Positive nuclear Ki-67 expression was seen as light brown staining. All stained areas demonstrating positivity for Ki-67 were identified at a magnification of ×20. The total number of 1000 positively stained cells were counted in 10 representative fields of the section.

Statistical analysis

The collected data were entered in a Mircosoft Excel sheet and statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) software, version 20.0. The normal distribution of the number of positive cells was done by one-way analysis of variance (ANOVA) test. Comparison of three groups with respect to the number of positive cells; percentage of positive cells and score was made by one-way ANOVA test. Pairwise comparison of three groups was made using Tukey's multiple post hoc test.

Ethical Approval

Ethical approval for this study is, The protocal No.(Pr.80/IEC/SIBAR/2016) was provided by IEC-SIBAR institute of Dental sciences, Guntur on 24 November 2016.


  Results Top


The mean value of positive cells in Group I (Controls) was 308.60 ± 64.18, Group II (OL) was 399.40 ± 86.2 and Group III (ELP) was 356.60 ± 47.08. The number of positive cells was more in leukoplakia and ELP. Statistical analysis was done using the one-way ANOVA test and a statistically significant difference of mean was obtained (P = 0.0207). Pairwise comparison of three groups concerning the percentage of positive cells was done using Tukey's multiple post hoc test. A high statistical significance was noticed on comparison of means in between Group I (30.86) and Group II (39.94) (P = 0.0156). However, there was no statistically significant difference between Group I (30.86) and Group III (35.66) (P = 0.2698) and Group II (39.94) and Group III (35.66) (P = 0.3490) [Table 1].
TABLE 1: Pair-wise comparison of the percentage of positive cells in three groups by Tukey'S multiple post hoc test

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  Discussion Top


The present study analysed the immunohistochemical expression of Ki-67 in controls, OL and ELP. The expression of Ki-67 immunopositive cells was more in OL when compared to controls and ELP. In ELP, the expression of Ki-67 immunopositive cells was more than controls and less than OL, i.e., the presence, location and pattern of cell proliferation in the oral leukoplakic epithelium were more and statistically significant.[6] The expression of p53 protein and Ki-67 antigen in OL with or without epithelial dysplasia by using Immunohistochemistry(IHC) and the result were, In the OL with or without epithelial dysplasia, the Ki-67 expression was more than normal epithelium,[7] because it may accelerate the rate of genetic alterations towards oral carcinogenesis. Identifying such proteins in leukoplakia contributes to assessing the malignant transformation probability for a given lesion.[8] The rate of Ki-67 expression in OLP was more than in normal mucosa. The proliferative status of the lesion and increased cell proliferation in OLP is likely to be a secondary phenomenon, because of the damage inflicted on keratinocytes by infiltrating mononuclear cells in the sub-mucosa.[9] The Ki-67 expression was more in the OLP group than control group.[10] It was mainly seen in the parabasal layer, where the proliferating cells were restricted, rather than in the basal layer. In LP cases, the Ki-67 expression was less pronounced than compared to OL, but the expression was more than the normal mucosa.[11] By this in OL the immunopositive cells were more significant.


  Conclusion Top


The results of the present study emphasize that the expression of Ki-67 was increased in OL when compared to ELP and controls. In OL and ELP, the expression was seen in basal and parabasal layers of epithelium, whereas in normal mucosa it was restricted to the only basal layer, suggesting that Ki-67 can serve as a proliferation marker that can be useful for early detection of malignant transformation and, in turn, can be necessary for patient prognosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Cormach DH. Textbook of Ham's histology. In: Barnes D, Winters R, Maxwell ME, editors. 9th ed. Philadelphia: J. B Lippincott Company; 1987. p. 1-23.  Back to cited text no. 1
    
2.
Pardee AB. G1 events and regulation of cell proliferation. Science 1989;246:603-8.  Back to cited text no. 2
    
3.
George A, Sreenivasan BS, Sunil S, Varghese SS, Thomas J, Devi G, et al. Potentially malignant disorders of oral cavity. J Oral Maxillofac Pathol 2011;2:95-100.  Back to cited text no. 3
    
4.
Warnakulasuriya S, Newell W, Van der Waal I. Nomenclature and classification of potentially malignant disorders of the oral mucosa. J Oral Pathol Med 2007;36:575-80.  Back to cited text no. 4
    
5.
Zhang L, Michelsen C, Cheng X, Zeng T, Priddy R, Rosin MP. Molecular analysis of oral lichen planus. A premalignant lesion?. Am J Pathol 1997;151:323-7.  Back to cited text no. 5
    
6.
Birajdar SS, Radhika M, Paremala K, Sudhakara M, Soumya M, Gadivan M. Expression of Ki-67 in normal oral epithelium, leukoplakic oral epithelium and oral squamous cell carcinoma. J Oral Maxillofac Pathol 2014;18:169-76.  Back to cited text no. 6
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7.
Mandol K, Mandal R, Sarkal BC. A Study of ki-67 expression and its clinicopathological determinants in nondysplastic oral leukoplakia. Contemp Clin Dent 2016;7:493-9.  Back to cited text no. 7
    
8.
Piattelli A, Rubini C, Fioroni M, Iezzi G, Santinelli A. Prevalence of p53, bcl-2 and Ki-67 immunoreactivity and of apoptosis in normal oral epithelium and in premalignant and malignant lesions of the oral cavity. J Oral Maxillofac Surg 2002;60:532-40.  Back to cited text no. 8
    
9.
Taniguchi Y, Nagao T, Maeda H, Kameyama Y, Warnakulasuriya KA. Epithelialcell proliferation in oral lichen planus. Cell Prolif 2002;35:103-9.  Back to cited text no. 9
    
10.
Bashardonst N, Modabbernia S, Shiva A, Jalali R. Immunohistochemical analysis of Ki-67 expression in Oral Lichen Planus Lesions. JDRPS 2015;4:25-30.  Back to cited text no. 10
    
11.
Kumar KV, Chaithanya KH, Punde P, Thorat A, Jangam AG, Deepthi S. Comparative evaluation of imunohistochemical expression of Ki-67 in oral lichen planus, oral leukoplakia and normal mucosa cases. J Int Oral Health 2015;7:82-7.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1]



 

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