Assessing ¹⁸F-FDG PET/CT Uptake and its Correlation with Molecular Biomarkers in Penile Cancer

Background

Penile Cancer is a rare and aggressive disease. Related to complex metabolic processes.

Objective

This study investigates the effectiveness of¹⁸F-FDG PET/CT as a noninvasive method in evaluating penile cancer patients, focusing on the correlation between tissue expression of key tumor markers involved in glucose metabolism and proliferation, and the uptake of ¹⁸F-FDG.

Methods

Fifty-one patients were selected and underwent ¹⁸F-FDG PET/CT-based staging. Semiquantitative analysis was performed using the maximum standardized uptake value (SUV_max) and volumetric SUV (SUV_2SD). Tissue expression analysis of GLUT-1, hexokinase-II, Ki67, p16, and p53 was performed by tissue microarray. PCR evaluated HPV DNA.

Results

Warty SCC showed the highest SUV value and significant differences in SUV_max (p=0.015). Higher SUV_max and SUV_2SD values were observed in grade 3 tumors. In typical invasive SCC, grade 3, HPV+, p16-negative, p53-negative, GLUT-1 i-3, and HK-II i-3 tumors showed a higher mean SUV. The Ki-67 value significantly differed for grade 3 tumors (p=0.001) and HK-II i-1 tumors (p=0.036). Ki-67 positivity was also higher in HPV-, p16 i-2, p53 i-3, and GLUT-1 i-3 tumors; none of the differences were statistically significant.

Conclusions

The study highlights correlations between the uptake of ¹⁸F-FDG and the expression of markers associated with glycolytic metabolism in penile cancer. It suggests a potential trend where increased expression of glucose transport markers is linked to higher histological grades and Ki-67 expression. There were no significant differences regarding HPV positivity, demonstrating the complexity of penile cancer molecular biology and need more studies with a higher number of patients.

Graphical Abstract