CD99 and cervical cancer: The upregulated ligand receptor pairs in the cervical cancer group were SPP1 − CD44, FN1 − SDC4, FN1 − SDC1, FN1 − CD44, CD99 − CD99, and the downregulated ligand receptor pairs were PPIA – BSG, LGALS9 − P4HB, LGALS9 − CD44 (Figure 8d).