H2BC21 and oropharynx squamous cell carcinoma: A direct comparison of the effect of irradiation of HeLa and oropharyngeal squamous cell carcinoma by high-LET α-particles and protons or by low-LET protons or X rays/γ-radiation revealed that the H2B ubiquitylated signaling and repair of complex DNA damage (CDD) is induced only by high LET, which contributes significantly to cell survival after irradiation [58].