Silibinin plus Stupp protocol as conversion therapy for unresectable glioblastoma with pSTAT3 expression, an oasis in the desert? A case report description.

Glioblastoma represents adulthood's most frequent and aggressive primary brain tumor. The gold standard in the treatment remains radical resection followed by concomitant chemo-radiation therapy according to the STUPP protocol. Despite the therapy, the prognosis remains poor. Thus, one main objective in neuro-oncology research is identifying novel therapeutic targets to improve life expectancy. In this regard, recent advances underline the importance of pSTAT3 expression in the Glioblastoma microenvironment in terms of cancer initiation and progression. Therefore, pSTAT3 inactivation due to Silibinin action may prove to be an additional therapeutic option for Glioblastoma patients. Here we report the case of a 52-year-old patient diagnosed with an unresectable right front-temporal-insular Glioblastoma by biopsy. The patient was directed upfront to concomitant chemoradiotherapy treatment with Temozolomide and Silibinin, which had a neoadjuvant effect, obtaining an objective response that made radical surgery possible. The subsequent immunohistochemistry analyses showed a moderate expression of the signal transducer and activator of transcription 3 on reactive astrocytes surrounding tumor cells. To our knowledge, this is the first report concerning the activity of Silibinin as conversion therapy in concomitance to standard treatment and could lay the foundation for the design of prospective trials aimed at validating this scheme as a standardized neoadjuvant option for unresectable Glioblastoma patients.