TPO mRNA levels decreased with the tumor progression: in poorly differentiated (grade 3) tumors they were 1.6-fold lower than in moderately differentiated (grade 2) tumors (P-value < 0.05) and 2.3-fold lower than in well-differentiated (grade 1) tumors (P-value < 0.01), with the P-value for trend of 0.002. The gene discussed is TPO; the disease is neoplasm.