The purpose of this paper is to provide an empirical test of the commercialization route chosen by university scientists funded by the National Cancer Institute (NCI) at the NIH and how their chosen commercialization path is influenced by whether or not the university technology transfer office is involved. In particular, the paper identifies two routes for scientific commercialization. Scientists who select the TTO route by commercializing their research through assigning all patents to their university TTO account for 70% of NCI patenting scientists. Scientists who choose the backdoor route to commercialize their research, in that they do not assign patents to their university TTO, comprise 30% of patenting NCI scientists. The findings show a clear link between the commercialization mode and the commercialization route. Scientists choosing the backdoor route for commercialization, by not assigning patents to their university to commercialize research, tend to rely on the commercialization mode of starting a new firm. By contrast, scientists who select the TTO route by assigning their patents to the university tend to rely on the commercialization mode of licensing.