A study performed in the USA on 30 OCCC has shown these tumors to be densely infiltrated by CD8 and PD-1 positive T cells, alongside consistent PD-L1 expression (evaluated with E1L3N clone, the positivity was defined as greater than or equal to 5% of tumor cells with PD-L1 positivity) across both neoplastic and immune compartments. This evidence concerns the gene CD8A and neoplasm.