Definition
An abnormal growth of cells resulting from uncontrolled cell proliferation.
Related Claims
- Aneuploid tumors inactivate Stat1 signaling with increased Myc activity
- Chromosomal instability promotes immune cell infiltration into tumors
- p53 loss is common but not enriched in chromosomally unstable tumors
- Stat1 inactivation mechanism is conserved between mouse and human aneuploid cancers
- Aneuploid cancers inactivate Stat1 to circumvent immune surveillance
- Established glioblastoma subtype classifiers are variably expressed within tumors
- Proliferation and immune response programs vary across individual glioblastoma cells
- Hypoxia-related transcriptional programs are variably expressed in glioblastoma cells
- Copy number-independent gene signature correlates with tumor grade and patient survival
- Tumors contain multiple subclones with spatial and temporal heterogeneity
- Subclonal driver events determine therapy response and tumor evolution
- scWGS platform detects copy number variants via shallow sequencing
- Bulk sequencing masks intratumoral copy number heterogeneity
Synthesis
Tumors are now firmly established as complex, heterogeneous ecosystems consisting of multiple genetically and phenotypically distinct subclones that vary both spatially across different tumor regions and temporally as they accumulate driver mutations and other genetic alterations over time. This intratumoral heterogeneity, particularly evident in studies of glioblastoma through single-cell RNA sequencing, reveals that individual tumor cells within the same mass exhibit variable expression of transcriptional programs related to proliferation, hypoxia response, immune regulation, and established molecular subtype classifiers, challenging the validity of population-level gene expression signatures derived from bulk sequencing approaches that mask true cell-to-cell variability. A key mechanistic relationship emerging across studies is that chromosomal instability, while generating immunogenic signals that increase immune cell infiltration into tumors, simultaneously creates selective pressure for specific immune evasion mechanisms, most notably the inactivation of Stat1 signaling often coupled with increased Myc activity in aneuploid cancers, representing a conserved evolutionary solution that enables chromosomally unstable cells to overcome fitness costs and achieve malignant transformation. What remains contested is the extent to which gene expression signatures that correlate with clinical outcomes in bulk tumor analyses reflect genuine biological programs versus artifacts of proliferation confounding and averaging across heterogeneous cell populations, with single-cell approaches increasingly questioning whether population-level molecular subtypes represent stable cellular states or simply statistical composites of diverse intratumoral populations.