LINC00221 and neoplasm: The expression of LINC00221 was markedly reduced in the tumor xenografts of nude mice transplanted with LINC00221-deficient Huh7/MHCC97-H cells, while its expression was considerably elevated in the tumor xenografts of mice transplanted with Huh7/MHCC97-H cells overexpressing LINC00221 (Additional file 3: Figure S3).