Immunohistochemical Analysis of TP53 and PTEN Expression in Glioblastoma Multiforme Patients of Western Rajasthan, India: An Observational Study

Abstract

Introduction: Glioblastoma Multiforme (GBM) is the most aggressive brain tumour with a dismal prognosis. Very few studies on its diagnosis, prognosis and therapeutics have been attempted in the past on Indian population. Standard treatment of this highly aggressive tumour yields little survival benefit; hence, greater attention is now being paid to personalised treatment and, correspondingly, to the expression of specific molecular markers with the goal of assessing their possible therapeutic as well as prognostic significance. Aim: To estimate the proportion of Tumour Protein 53 (TP53) and PTEN (Phosphatase and Tensin Homolog) expression in GBM patients of Western Rajasthan, India. Materials and Methods: This study was a ambispective, single institutional observational study done on 35 brain tissue biopsies of histopathologically diagnosed and confirmed cases of GBM based on the World Health Organisation (WHO) classification, 2007 received in Department of Pathology, Dr. Sampurnanand Medical College (Dr. SNMC), Jodhpur, Rajasthan, India, from January 2015 to December 2020 (January 2015 to September 2018:Retrospective and October 2018 to December 2020:Prospective) after applying inclusion and exclusion criteria. Immunohistochemical (IHC) analysis was done for TP53 and PTEN markers in all cases of GBM. The results were then applied for statistical analysis using Statistical Package for the Social Sciences (SPSS) version 22.0 software package (SPSS Inc., Chicago, IL, USA). The association between age and gender with TP53 and PTEN positive cases, respectively, was analysed by using Fisher’s-exact test and the results of the same were compiled. Results: The TP53 expression was seen in 32 cases (91.4%). The mean age of presentation of TP53 positivity was 50.3 years. Most of the TP53 cases occurred in the 41 to 50 and 61 to 70 years of age groups. In TP53 mutated cases, males were found more commonly affected as compared to females. Overall, the majority of cases (eight cases) occurred in the temporal region of the brain (25%). The relationship between age and gender with TP53 expression was found to be insignificant. PTEN expression was found absent (mutation positive) in 11 cases (32.4%). Mean age of these patients was 52.5 years. The male to female ratio was found to be 1.8:1. Regarding tumour location in the brain, most of the cases occurred unilaterally, with 45.4% (n=5) of cases occurring in the temporal region. The association between PTEN mutation with age and gender was not found to be significant. Conclusion: The higher prevalence of TP53 expression in the population suggests distinct genetic pathways that need to be studied in detail to have a better understanding of this highly aggressive tumour. The PTEN mutation was discovered to be prevalent in the population of Western Rajasthan and needs to be studied further on a large scale. The simultaneous presence of molecular markers in GBM cases would need to be considered before initiating any gene therapy for its improved effectiveness.

Keywords

• genetic pathways
• immunohistochemical grading
• molecular markers
• nuclear staining
• targeted therapy
• world health organisation classification 2007