PDCD1LG2 and cervical carcinoma: Genetic aberrations at the 9p24.1 chromosomal region, transcriptional regulation by factors such as interferons, oncogenic signaling pathways (e.g., JAK/STAT and RAS/ERK signaling), epigenetic modifications, and productive infection with HPV (in case of cervical cancer), may all play individual or synergistic roles in the regulation of PD-L1/PD-L2 (16–19).