Study Identifies 7.2% Average Dormant Cancer Cell Fraction Driving Tumor Recurrence

A team of researchers has determined that not all malignant cells within tumors divide continuously; instead, a subset enters a quiescent state, with this dormant fraction averaging 7.2% across cases.

This finding forms the core of a study published in the journal *Genome Medicine*, which highlights the particular danger posed by these dormant cells. According to Alexis Barr, an oncology specialist at King’s College London, they can withstand chemotherapy and subsequently reawaken to reignite tumor growth.

How dormancy confers intrinsic treatment resistance

The study further establishes that resistance to therapy is inherent in these dormant cells from the outset — present even prior to treatment initiation. These quiescent cells are frequently enveloped by macrophages producing the protein CXCL10, alongside fibroblasts — connective tissue cells known to support tumor progression. This cellular “shield” may impede both drug penetration and immune cell access to the targeted cancer cells.

Uncertainty over tumor–microenvironment control

Maria Sekrier, a study co-author from University College London, stated: “We do not yet know who is directing this process: the tumor or its guardians? The relationship between them is likely bidirectional.”

Therapeutic implications for future treatment design

The study authors conclude that next-generation therapies must simultaneously target both actively dividing regions of the tumor and its dormant zones.

Although dormant cells pose a serious clinical threat, their presence may, paradoxically, serve as a favorable prognostic indicator in certain contexts. Statistical analysis revealed that higher proportions of dormant cells in hormone-positive tumors correlate with longer recurrence-free survival.