Biology subjects

Gillis, A. J. M.

Publications and source records attributed to Gillis, A. J. M..

3 recordsLinked to original sources

bioRxiv2025

Identification and validation of liquid biopsy-based methylation biomarkers: a germ cell tumor subtype-specific study

Human germ cell tumors (GCTs) occur in infants, children, and adults, and present as germinomatous and/or non-germinomatous (embryonal carcinoma, teratoma, yolk sac tumor (YST), and choriocarcinoma) histologies at gonadal or extragonadal locations. Accurate subtyping is crucial for prognosis and treatment, but current clinical biomarkers lack sensitivity and specificity (serum proteins) or require a tissue biopsy (immunohistochemistry). Hence, less-invasive and improved subtype-specific biomarkers have potential for clinical utility. We conducted a meta-analysis of DNA methylation data (450K/EPIC array) from 15 (three original and 12 published) datasets including 713 GCTs, 109 healthy testis, and 221 healthy peripheral blood samples, revealing that GCT histology is the primary driver of methylation profiles, regardless of tumor location and patients age or sex. Per subtype, we identified differentially methylated regions as potential biomarkers. As proof of concept, we identified and validated two YST-specific biomarkers, i.e., APC and DPP7 promotor methylation, using methylation-sensitive restriction enzyme-based qPCR, of which DPP7 was also detectable in GCT serum-derived cell-free DNA. In conclusion, we present a novel method for in silico identification and in vitro and in vivo validation of YST subtype-specific liquid biopsy-based biomarkers. Our bioinformatic pipeline is easily transferrable encouraging additional applications in pan(pediatric)-cancer studies beyond GCTs.

cancer biology↗

bioRxiv2023

Cytogenetic resource enables mechanistic resolution of changing trends in human pluripotent stem cell aberrations linked to feeder-free culture

Since the first derivation of human pluripotent stem cells (hPSCs), the number of culture conditions has steadily increased, making hPSC culture more facile. Nonetheless, there remains the persistent issue of culture-acquired genetic changes, hampering the reproducibility of hPSC research and jeopardising their clinical use. Here, we utilised comprehensive karyotyping datasets from over 20,000 hPSC cultures sampled under different conditions to ascertain association of genetic changes with specific culture regimens. We found condition-dependent patterns of aberrations, with higher prevalence of chromosome 1q gains in recent years, associated with increased use of contemporary, feeder-free cultures. Mechanistically, we show the context-dependent selection of 1q variants is mainly driven by MDM4, a gene amplified in many cancers, located on chromosome 1q. To facilitate reproducibility of hPSC research and their safe clinical utility, we provide a unique hPSC karyotype resource for informing the risk assessment of genetic aberrations and developing strategies to suppress their occurrence.

cell biology↗

bioRxiv2023

Analysis of a mouse germ cell tumor model establishes pluripotency-associated miRNAs as conserved serum biomarkers for germ cell cancer detection

Malignant testicular germ cells tumors (TGCTs) are the most common solid cancers in young men. Current TGCT diagnostics include conventional serum protein markers, but these lack the sensitivity and specificity to serve as accurate markers across all TGCT subtypes. MicroRNAs (miRNAs) are small non-coding regulatory RNAs and informative biomarkers for several diseases. In humans, miRNAs of the miR-371-373 cluster are detectable in the serum of patients with malignant TGCTs and outperform existing serum protein markers for both initial diagnosis and subsequent disease monitoring. We previously developed a genetically engineered mouse model featuring malignant mixed TGCTs consisting of pluripotent embryonal carcinoma (EC) and differentiated teratoma that, like the corresponding human malignancies, originate in utero and are highly chemosensitive. Here, we report that miRNAs in the mouse miR-290-295 cluster, homologs of the human miR-371-373 cluster, were detectable in serum from mice with malignant TGCTs but not from tumor-free control mice or mice with benign teratomas. miR-291-293 were expressed and secreted specifically by pluripotent EC cells, and expression was lost following differentiation induced by the drug thioridazine. Notably, miR-291-293 levels were significantly higher in the serum of pregnant dams carrying tumor-bearing fetuses compared to that of control dams. These findings reveal that expression of the miR-290-295 and miR-371-373 clusters in mice and humans, respectively, is a conserved feature of malignant TGCTs, further validating the mouse model as representative of the human disease. These data also highlight the potential of serum miR-371-373 assays to improve patient outcomes through early TGCT detection, possibly even prenatally.

cancer biology↗