ABCG2 transcript in HNCs was highly expressed in undifferentiated (grade 4) tumor tissues in contrast to normal head and neck tissues (Figure 5C), while ABCG2 levels negatively correlated with patient prognosis (Figure 5D), implying that ABCG2 could serve as a prognostic marker for HNCs in clinics. The gene discussed is ABCG2; the disease is neoplasm.