Germ cell tumors are among cancers that can afflict pediatric patients, and although many patients with these cancers can be cured, the therapies are associated with significant toxicity and are not effective for some patients. Despite these deficiencies, there have been no new FDA approved therapies for germ cell tumors in over 25 years. We aim to develop new treatments based on recent discoveries that germ cell tumors send out small cellular packages, called extracellular vesicles (EVs). These EVs contain a range of different molecules that can be taken up by other cells. Importantly, in many other cancers EVs have been shown to strongly promote tumor growth. We have recently shown that EVs from germ cell tumors contain at least two types of molecules that are likely to contribute to tumor growth. One group of molecules we detected in germ cell tumor-derived EVs are small RNA molecules called miRNAs. These miRNAs can be detected in the serum of patients and are the basis for new clinical tests to identify malignant germ cell tumors in patients. In addition, we found that germ cell tumor-derived EVs contain several metabolites that seem likely to further cancer-like growth of cells. These miRNAs and metabolites represent potential therapeutic targets to improve germ cell tumor treatment. However, almost nothing is known about the mechanisms by which these miRNAs and metabolites promote disease progression; here, we seek to address those key knowledge gaps.