Hoxhaj I, Vukovic V, Boccia S, et al. - Researchers conducted this systematic review and meta-analysis to identify the single nucleotide polymorphisms (SNPs) that contribute to second primary cancer (SPC) development among head and neck cancer (HNC) survivors. PubMed, Scopus, and ISI Web of Science were searched for eligible studies published in English until January 31, 2020. Twenty-one studies, of moderate to good quality, were involved in the systematic review. Overall, 81 out of 122 investigated SNPs were significantly linked to the SPC risk. The identified SNPs in the systematic review and meta-analysis could serve as potential markers for identifying patients at high risk of developing SPC after primary HNC.