Chromosome instability is a hallmark of many tumors and correlates with the presence of extra centrosomes. However, a direct mechanistic link between extra centrosomes and CIN had not been previously established. [@ganem_mechanism_2009]

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It is well-established across multiple sources that extra centrosomes are associated with chromosomal instability in tumors, though the mechanistic relationship is more complex than initially presumed. While extra centrosomes can promote chromosome missegregation during cell division, multipolar divisions themselves are rare and typically produce inviable progeny, indicating that the presence of supernumerary centrosomes must drive chromosomal instability through alternative mechanisms, such as transient multipolar spindle intermediates that allow merotelic kinetochore attachments to accumulate before bipolar division. The relationship between chromosomal instability and tumor progression remains contested, as aneuploidy exhibits dual roles depending on context: elevated chromosomal instability drives spontaneous tumor formation in aged animals but paradoxically inhibits chemically or genetically induced tumorigenesis, suggesting that the fitness consequences of chromosomal instability vary with the initiating oncogenic event. Furthermore, chromosomally unstable tumors must overcome immune surveillance triggered by their aneuploid state, with evidence showing that aneuploid cancers consistently inactivate Stat1 signaling while increasing Myc activity to evade immune-mediated elimination, representing a conserved evolutionary solution that enables chromosomally unstable cells to achieve malignancy.

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