A new research paper was published in Oncotarget, Volume 16, on April 24, 2025, titled "PD-L1 and FOXP3 expression in high-grade squamous intraepithelial lesions of the anogenital region." Researchers Humberto Carvalho Carneiro, Rodrigo de Andrade Natal, José Vassallo and Fernando Augusto Soares from the Instituto D'Or de Pesquisa e Ensino and Rede D'Or studied early tissue changes caused by human papillomavirus (HPV) in the anal, vulvar, and penile regions. They found that high-grade pre-cancer lesions triggered stronger immune responses and showed higher levels of two immune-related markers, PD-L1 and FOXP3. These findings are important because they help explain how some HPV-related lesions progress to cancer while others heal on their own. High-risk HPV is known to cause several types of anogenital cancers. Before these cancers appear, the virus often leads to abnormal tissue changes known as high-grade squamous intraepithelial lesions. Many of these lesions disappear without treatment, but some become cancer-especially in people with weakened immune systems. This study explored how immune activity may play a role in this progression. The researchers examined tissue from 157 patients-95 males and 55 females-with either high-grade or low-grade HPV-related lesions. They found that T-regulatory cells, marked by the FOXP3 protein, were more common in high-grade lesions. These immune cells are known to suppress immune responses, which can allow infected or abnormal cells to grow. The team also found higher expression of PD-L1, a protein that helps cells evade immune detection, particularly in inflammatory immune cells. "Dense inflammatory infiltrates and high counts of FOXP3+ cells were significantly more frequent in patients with HSILs than in those with LSILsHR (p = 0.04 and 0.02, respectively). HSILs also exhibited higher PD-L1 expression (padj < 0.01 and < 0.01 for the SP142 and 22C3 clones, respectively), based on the Poisson generalized linear model." These findings suggest that HPV may begin avoiding the immune system early in infection, even before cancer develops. The combination of high FOXP3 and PD-L1 levels may create a protective environment for infected cells, making them harder for the body to eliminate. This immune evasion may allow the lesions to remain and, over time, become cancerous. The study also compared patients with and without HIV to assess whether immune health influenced the results. While those with compromised immune systems had more extensive lesions, PD-L1 and FOXP3 expression was also found in patients with healthy immune systems. This evidence shows that immune evasion by HPV can happen regardless of a person's immune status. Understanding how PD-L1 and FOXP3 function in early HPV-related lesions may help clinicians predict which lesions are more likely to become cancer. These insights could lead to new strategies for monitoring, treating, or preventing HPV-related precancerous lesions and cancer in the anogenital region. The study highlights how early immune system changes can play a key role in the development of HPV-related cancers.