PDCD1 and ovarian serous carcinoma: [14] This study found quite similar median numbers of PD-1+ TILs in high-grade serous ovarian carcinomas: approximately n = 12 PD-1+ TILs/mm2 (tumor and stroma not separated), our study: n = 12 PD-1+ TILs/mm2 (intratumoral only), and it is remarkable that this small subpopulation of T cells obviously has a biological significance as measured by patient prognosis.