DDR2 and squamous cell lung carcinoma: In the case of DDR2, these mutations are present in 3–4% of patients with lung squamous cell cancer (Hammerman et al., 2011) and have been reported in other cancers at comparable frequencies including lung adenocarcinoma, cervical carcinoma, gastric carcinoma, bladder carcinoma, melanoma, colorectal cancer, head, and neck cancer (Beauchamp et al., 2014).