While it might be instructive to consider different cancer subtypes (e.g., by grade, histology, etc.)within a single tumor location independently, such subtype information was not generally reported by SEER during the decades-long time frame we considered (e.g., HPV status in head and neck cancer and HER-2 status for breast cancer have been reported only since 2010). Here, ERBB2 is linked to head and neck cancer.