AFP and liver cancer: Wilcoxon's test also showed that AFP-positive (average rank 45.69, 45.29, and 44.27) and AFP-negative (average rank 31.30, 31.53, and 32.11) liver cancer cells had significantly different sensitivities to the three combination regimens (W = 1440.000, Z = −2.802, P=0.005; W = 1450.500, Z = −2.679, P=0.007 and W = 1477.000, Z = −2.368, P=0.018), with AFP-positive liver cancer cells being more sensitive than AFP-negative cells.