Orphan cytochromes P450 (CYP) are enzymes whose biological functions and substrates are unknown. However, the use of new experimental strategies has allowed obtaining more information about their relevance in the metabolism of endogenous and exogenous compounds. Likewise, the modulation of their expression and activity has been associated with pathogenesis and prognosis in different diseases. In this work, we review the regulatory pathways and the possible role of orphan CYP to provide evidence that allow us to stop considering some of them as orphan enzymes and to propose them as possible therapeutic targets in the design of new strategies for the treatment of diseases associated with CYP-mediated metabolism.

The 5-year relative survival rate estimate of treated patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) is ∼50% since they generally present with tumor progression, relapse, metastasis, and/or chemoresistance. The expression of cytochrome P450 (CYP) enzymes in malignancies can affect the pharmacology of drugs commonly used in chemotherapy or confer susceptibility to development of chemical carcinogenesis; in addition, their specific tumor expression can be used as a therapeutic target. Using qPCR and Western blot assays, the expression of CYP1B1, CYP2E1, CYP3A4, and CYP3A5 were analyzed in a cohort of tumor tissue paired with non-malignant adjacent tissue of patients with NRSTS. The mRNA and protein expression of CYP1B1, CYP2E1, and CYP3A4 were significantly increased in tumor tissue. We propose that the expression of these isoforms is related to carcinogenesis and chemoresistance frequently observed in these neoplasms.

Pediatric soft-tissue sarcomas (STSs) are aggressive malignancies with poor prognoses, particularly in recurrent and metastatic cases. Standard therapies, such as cytotoxic chemotherapy, offer limited survival benefits and carry significant toxicities, underscoring the urgent need for innovative therapeutic approaches. CYP2W1, a tumor-specific monooxygenase enzyme, has emerged as a promising therapeutic target due to its aberrant expression in various cancers. However, its role in pediatric STSs remains poorly understood. This study evaluated CYP2W1 expression in 42 pediatric STS samples across seven histological subtypes using qPCR and Western blot analyses. High CYP2W1 expression was detected in 69% of tumor samples at the mRNA level and in 40.5% at the protein level, compared to absent or negligible expression in matched normal tissues (p < 0.001). Synovial sarcoma and rhabdomyosarcoma subtypes exhibited the highest CYP2W1 protein expression, at 70% and 62.5%, respectively. Furthermore, CYP2W1 expression was significantly associated with higher histological grade, advanced tumor stage, and a trend toward reduced overall survival (p = 0.082). These findings indicate that CYP2W1 is aberrantly expressed in a subset of pediatric STSs, contributing to tumor aggressiveness and highlighting its potential as a novel therapeutic target for these challenging malignancies.

Pediatric soft tissue sarcomas (STS) are aggressive malignancies with poor prognoses, particularly in recurrent and metastatic cases. Standard therapies, such as cytotoxic chemotherapy, offer limited survival benefits and carry significant toxicities, highlighting the urgent need for innovative ther-apeutic approaches. CYP2W1, a tumor-associated monooxygenase enzyme, has emerged as a promising therapeutic target due to its aberrant expression in various cancers; however, its role in pediatric STS remains poorly understood. This study evaluated CYP2W1 expression in 42 primary pediatric STS samples across seven histological subtypes using qPCR and Western blot analyses, investigating its association with clinicopathological variables and survival outcomes. High CYP2W1 expression at both mRNA and protein levels was observed in 69% and 40.5% of STS tumor samples, respectively, compared to absent or negligible expression in matched normal tissues (p < 0.001). Aberrant CYP2W1 protein expression was predominantly found in synovial sarcoma and rhabdomyosarcoma subtypes, at 70% and 62.5%, respectively. Additionally, CYP2W1 ex-pression correlated with higher histological grade, advanced tumor stage, and showed a trend toward reduced overall survival (p = 0.082). These findings demonstrate that CYP2W1 is aberrantly expressed in a subset of pediatric STS, contributing to tumor aggressiveness and highlighting its potential as a promising therapeutic target for this malignancy.