Furthermore, certain groups only use athymic nude mice, others use non-obese diabetic severe combined immunodeficiency mice and some employ both strains. Significantly, these different techniques have all led to successful tumor growth. Another recurring theme that emerges in PDX development is that tumors are taken as quickly as possible from the time of biopsy and then injected into the immunodeficient mice. Our group and others proceed in this manner due to the belief that the time from tumor excision to xenograft implantation is important. However, there is no information in the literature to suggest that tumor chunks must be injected/implanted as soon as possible into the mice. In addition, while mouse-to-mouse passage is typically performed as rapidly as possible, there is again, little data to support the necessity of this practice. Due to the uncertainty regarding optimal harvesting and implantation techniques, we undertook this study to determine whether there was a relationship in the SMANT hydrochloride growth potential of the PDX based on the time delay from initial tumor excision to its ultimate implantation in the mice. In addition, we sought to determine whether the storage medium used during the processing delay affected PDX viability. This work is important since there are a number of factors outside of the researcher��s control that can influence the ability to obtain tumor biopsies from consented patients in a timely manner. Moreover, once PDXs are established, re-implantation requires the availability of recipient mice and their dissemination to other laboratories may require shipment. Both of these issues can lead to delays in reimplantation. Our results demonstrate the tumor is still viable and capable of growing in the next generation of mice up to at least 48 hours after the initial tumor excision and that the nature of the storage solution, be it tissue culture medium or saline solution, has no effect on tumor growth. Furthermore, we revealed that fresh patient tissue from the Spermidine trihydrochloride operating room is viable and can be used to establish a new PDX up to at least 24 hours after initial excision from the patient. The ability to delay tumor implantation has important implications with regard to sharing of these resources as well as the logistics of initial PDX establishment and subsequent maintenance. We powered this study to detect a difference in PDX viability between the first and last time points.