PLK1 and cervical cancer: Although several researches involved PLK1 in cervical cancer (Yang et al., 2017; Li et al., 2011; Zhang et al., 2009; Gao et al., 2006; Zuco et al., 2015; Chhavi et al., 2010), PLK1 expression in cervical cancer was detected with single methods and small samples by those studies.