Figure 6.

Rituximab treatment prevents lymphoma onset without affecting Gastric PDX engraftment. A. A Lymphoma PDX (GTR0134) was subcutaneously implanted in 12 NOD/SCID mice. Four days after implant, 3 animals were treated with physiologic solution (‘Vehicle’), 3 with Rituximab i.p. 25 mg/kg, 3 times/week for 1 week (‘Ritux i.p.1w’), 3 with Rituximab i.p. 25 mg/kg, 3 times/week for 1 week and once a week for the following 3 weeks (Ritux i.p.4w), 3 with Rituximab i.v. 10 mg/kg, 3 times/week for 1 week (Ritux i.v.1w). The graph shows the tumor growth curves from the day of implant (day 0). Rituximab treatment completely inhibited lymphoma growth in mice. B. A gastric PDX (GTR0108) was subcutaneously implanted in 12 NOD/SCID mice. Four days after the implant, mice were divided in 4 groups and treated as in A. The graph shows the tumor growth curves from the day of implant (day 0). Rituximab treatment did not hamper gastric carcinoma growth. C. Gastric tumors received from March to August 2016 were implanted in at least 2 NOD/SCID mice; one of them was untreated (‘NT’), one was treated with Rituximab i.p. 25 mg/kg 3 times/week for 1 week and once a week for the following 3 weeks (Ritux). The graph reports the percentages of Gastric, Lymphoma and Mixed PDX onset in mice undergoing the different treatments. As shown, Rituximab treatment completely prevented the onset of lymphomas (18/18 Gastric PDXs in the Rituximab group). D. The gastric tumor from patient GTR0271 (upper panels) originated a Gastric PDX when grown in a Rituximab-treated mouse (middle panels) and a Lymphoma PDX when grown in an untreated animal (lower panels). H&E, pan-cytokeratin and CD20 staining confirmed the different histology of the PDXs. The EBV score, negative in the donor tumor and in the Gastric PDX and highly positive in the Lymphoma PDX, is also reported in the figure.