Sensitivity Assessment of Wilms Tumor Gene (WT1) Expression in Glioblastoma using qPCR and Immunohistochemistry and its Association with IDH1 Mutation and Recurrence Interval

Abstract

Purpose

Wilms tumor 1 (WT1) gene has recently shown a role in gliomagenesis, making it a potential immunotherapy target in glioblastomas. We aimed to investigate the most sensitive method to detect WT1 expression in glioblastoma and explore the relationship between WT1 expression, IDH1 mutation and recurrence interval.

Patients and Methods

Clinical data were collected from 44 patients with glioblastomas, treated with adjuvant therapies. WT1 expression was assessed in all cases using immunohistochemistry (IHC), while its gene expression was assessed in 13 clustered samples using polymerase chain reaction (qPCR). IDH1 mutation was assessed using IHC. The sensitivity between IHC and RT-qPCR was examined. Kaplan–Meier curves were used to compare the recurrence-free interval (RFI) between IDH1 and WT1 expression groups.

Results

IDH1^wildtype was found in 26 cases (59.1%) and the remaining 18 cases (40.9%) were IDH1^mutant. Through IHC, WT1 was overexpressed in 32 cases (72.7%), partially expressed in 9 cases (20.5%) and not expressed in only 3 cases. For the 13 cases tested by qPCR, 6 cases showed WT1 upregulation and 7 cases showed WT1 downregulation. There was no significant difference in WT1 expression among cases with different RNA concentrations regardless the testing method (p-value >0.05). However, the difference between IHC and qPCR was significant. IDH1^mutant cases with WT1 overexpression showed significant difference in RFI (p-value =0.048).

Conclusion

Parallel testing for WT1 expression using IHC and qPCR is not reliable. However, IHC provides more accurate results. Moreover, IDH1^mutant glioblastomas with WT1 overexpression are associated with late RFI particularly if temozolomide with additional chemotherapies are used.

Keywords:

• glioblastoma
• IDH1 mutation
• WT1 expression
• chemotherapies
• PCR sensitivity

Data Sharing Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethical Approval

Ethical approval for this study was granted by the National Biomedical Ethics Committee at King Abdulaziz University (HA-02-J-008) (Reference No. 189-19). All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Consent to Participate

All contributors have given consent to participate in the study.

Author Contributions

MK, idea, IRB submission, writing, study design and data, histological analysis. NS, statistical analysis SB, data provider, writing, analysis AK, study design, statistical analysis, PCR analysis, writing, editing, YM, data entry, tissue collection, writing AB, data entry, tissue collection RS, data entry, tissue collection, writing BG, data analysis, editing, submission, consultation AL, data provider, IRB submission FM, tissue collection, IRB submission, IHC SH, data interpretation All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

All authors reported no conflicts of interest for this work.

Additional information

Funding

The study is sponsored and funded by “Deanship of Scientific Research of King Abdulaziz University, Jeddah, Saudi Arabia” (Code No. G: 81-828-1441).