GLPp16 gene amplification induces susceptibility to high-grade urothelial carcinoma

Abstract

Background: Urothelial carcinoma is a common malignant tumor of the urinary system, with prognosis linked to pathological grade and TNM stage. Alterations in chromosomes 3, 7, and 17, along with the P16 locus on chromosome 9 (CSP3, CSP7, CSP17, and GLPp16), are associated with cancer progression and may serve as important biomarkers. This study aimed to explore the relationships between these chromosomal factors and the pathological grade and TNM stage of UCC, potentially leading to a novel diagnostic approach that enhances patient stratification and treatment planning.

Methods: A retrospective analysis was conducted on 149 patients to evaluate the correlation between CSP3, CSP7, CSP17, GLPp16, TNM stage, and pathological grade using chi-square tests and logistic regression. Immunohistochemistry was employed to assess the associated changes.

Results: Univariate analysis indicated that only CSP7 and GLPp16 were significantly associated with pathological grade. Logistic regression linked GLPp16 and gender to pathological grade in urothelial carcinoma. A nomogram model incorporating these factors demonstrated reliable calibration in the training set (non-significant Hosmer-Lemeshow test, P = 0.436; AUC = 0.785, 95% CI: 0.707 - 0.863) and effective discrimination in the test set (AUC = 0.740, 95% CI: 0.559 - 0.920). Immunohistochemistry revealed P16 gene deletion in low-grade urothelial carcinoma and amplification in high-grade urothelial carcinoma.

Conclusion: Mutations at the GLPp16 were significantly correlated with the pathological grade of urothelial carcinoma. Additionally, the amplification of GLPp16 was recognized as a contributing factor to the development of high-grade urothelial carcinoma.

Keywords: FISH; GLPp16; nomogram; pathological grading; urothelial carcinoma.

Figure 1

Cells without mutations exhibit two green fluorescent signals and two red fluorescent signals (A, B). (C) Shows the deletion of GLPp16. (D-G) Sequentially display the amplifications of CSP3, CSP7, CSP17, and GLPp16.

Figure 2

(A) A pie chart illustrating the distribution of FISH detection results for all patients in the training set was presented, depicting the state distribution of four FISH probes. (B) It described a flip chart showing the distribution of various types of positive FISH probe combinations. The horizontal axis used connected points to indicate different types of positive FISH probe combinations, while the vertical axis presented the patient count for specific combinations. The horizontal blue bars represented the positive counts for each FISH probe. FISH, Fluorescence In Situ Hybridization; CSP, Chromosome-specific centromere probe; GLP, Gene locus-specific probe.

Figure 3

(A) CSP3 and CSP17 failed to show a significant correlation with the pathological grading of urothelial carcinoma, whereas CSP7 and GLPp16 were statistically associated with it. χ2(CSP3) = 0.97, χ2(CSP17) = 0.36, p > 0.05; χ2(CSP7) = 9.39, χ2(GLPp16) = 25.34, p < 0.05. (B) CSP3, CSP7, and GLPp16 showed no significant correlation with the TNM staging of urothelial carcinoma. χ2(CSP3) = 5.28, χ2(CSP7) = 4.66, χ2(CSP17) = 2.99, χ2 = 15.19, p > 0.05. *p < 0.05, #p > 0.05.

Figure 4

(A) Forest plot showing the correlation between FISH assay results and tumor grade. (B) A regression model was used to construct a FISH-clinical nomogram to predict the risk of high-grade pathological grading in patients with urothelial carcinoma. The risk score could be calculated based on the regression formula. (C) DCA of nomogram in training set. (D) Calibration curve of the cytogenetic-clinical nomogram in the training set, Hosmer-Lemeshow test: p = 0.436. Receiver operator characteristic curve of the cytogenetic-clinical nomogram in the training set (E) and validation set (F).

Figure 5

(A) Deletion of GLPp16 in low-grade urothelial carcinoma. (B) Unmutation of GLPp16 in high-grade urothelial carcinoma. (C) Amplification of GLPp16 in high-grade urothelial carcinoma.