H2BC9 and cervical cancer: PPI analysis of the SLE pathway revealed 9 functional interaction modules of histone variants (HIST1H2BO, HIST1H4A, HIST1H2BD, HIST1H2BL, HIST1H2BJ, HIST1H2BH, HIST1H4E, HIST1H4K and HIST3H2BB) that are associated with the prognosis of cervical cancer patients (Fig. 8).