Relationship between number of GFP-positive CTCs in a 7.5-ml blood sample from gastric cancer patients and pathological findings in the patients. The dots are the numbers of GFP-positive CTCs in the patient samples. The bottom and top of the box represent the lower and upper quartiles, and the band across the box shows the median. The lower and upper bars at the ends of the whiskers show the lowest data point within 1.5 interquartile ranges of the lower quartile, and the highest data point within 1.5 interquartile ranges of the upper quartile, respectively. a, Tumour invasion depth (T1–T4 indicate increasing depth). b, Lymphatic metastasis (N0 = negative, N1–3 = positive). c, Distant metastasis (M0 = negative, M1 = positive). d, Histological type (differentiated type and undifferentiated type). e, Lymphatic invasion (L0 = negative, L1 = positive). f, Venous invasion (V0 = negative, V1 = positive), *p < 0.05. Although only venous invasion displayed a statistically significant difference, there were some trends towards an increase in CTC number with increasing disease progression.