Anal intraepithelial neoplasia is a precursor lesion of anal squamous cell carcinoma

Recently released oncotarget “PD-1 / PD-L1 expression in anal squamous intraepithelial lesions“which reported that the presence and distribution of CD8 lymphocytes and the presence of PD-1 lymphocytes and PD-L1 epithelial cells were assessed.

CD8 lymphocytes were observed more frequently in HSIL compared to LSIL in the lamina propria or intraepithelial.

PD-1 lymphocytes were observed more frequently in HSIL than in LSIL.

There was no difference between HSIL and LSIL for PD-L1 epithelial cells.

Anal dysplastic lesions are accompanied by an inflammatory lymphocytic infiltrate expressing CD8 and PD-1, which is more common in high-grade lesions.

Anal intraepithelial neoplasia (AIN) is the precursor lesion of anal squamous cell carcinoma (ASCC).”

Dr. Margot Bucau, Bichat-Claude Bernard Hospital

Dr. Margot Bucau from The Bichat-Claude Bernard Hospital said, “Anal intraepithelial neoplasia (AIN) is the precursor lesion of anal squamous cell carcinoma (ASCC).

Since 2012, lower anogenital squamous terminology has recommended the naming for HPV-associated squamous lesions of the lower anogenital tract as low-grade and high-grade squamous intraepithelial lesion.

Oncogenic infection with HPV plays a crucial role in the development of cervical and anal lesions, through integration of viral DNA into epithelial cells and activation of the early oncogenic proteins E6 and E7. This causes downregulation of tumor gene deletion, in particular TP53 and Rb, and upregulation of p16.

In the cervix, HPV-related cancers often have increased infiltration by immune cell populations, including cytotoxic CD8 T cells, which correlates with better response to chemoradiation and increased survival by compared to immunosuppressed tumors.

In addition, p16 positive tumors were found to have higher tumor infiltrating lymphocyte density and better recurrence-free survival.

The Bucau research team concluded in their Oncotarget research paper, “our exploratory study highlights the interest of the PD-1 / PD-L1 pathway in anal dysplasia and the importance of further exploring the different mechanisms of the immune microenvironment in the progression of anal intraepithelial lesion. It suggests the potential role of therapeutic molecules targeting the immune response in slowing tumor progression in some patients with HSIL.“