Science News from research organizations Scientists find the genetic switch that makes pancreatic cancer resist chemotherapy Date: March 3, 2026 Source: Duke-NUS Medical School Summary: Scientists have identified a crucial molecular switch that decides whether pancreatic cancer cells resist chemotherapy or respond to it. The key player, a gene called GATA6, keeps tumours in a more structured and treatable form—but it gets shut down by an overactive KRAS-driven pathway. When researchers blocked that pathway, GATA6 levels rebounded and cancer cells became more sensitive to chemo. The discovery could help turn some of the toughest pancreatic tumours into ones doctors can better control. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Zhong et al. report the critical role of oncogenic KRAS/ERK/JUNB signaling in suppressing GATA6, the master regulator of differentiation in pancreatic cancers. Key proteins in pancreatic cancer xenografts were detected by immunohistochemical staining, with the resulting photomicrographs enhanced in color and texture with the DeeVid AI tool. Credit: Zheng Zhong and Xinang Cao, Duke-NUS Medical School Researchers at Duke-NUS Medical School have discovered a molecular "switch" that determines whether pancreatic cancer cells respond to chemotherapy or resist it. The finding points to a way to potentially shift some of the most treatment resistant tumors into a state where existing drugs can work more effectively. The study, published in the Journal of Clinical Investigation , explains how this switch operates at a molecular level. The results suggest that pairing targeted therapies with standard chemotherapy may improve outcomes for patients whose tumors no longer respond to treatment. Why Pancreatic Cancer Is So Difficult to Treat Pancreatic cancer is one of the deadliest cancers worldwide. In Singapore, it ranks as the ninth most common cancer but the fourth leading cause of cancer related death. Because symptoms often appear late and current treatments have limited impact, most patients depend on chemotherapy, which typically provides only modest benefit. Over the past decade, scientists have identified two main molecular subtypes of pancreatic cancer, classical and basal. Tumors in the classical subtype tend to be more organized at the cellular level, and patients with this form are more likely to respond to treatment. In contrast, basal subtype tumors are more disorganized and aggressive, and they are often resistant to chemotherapy. Importantly, pancreatic cancer cells are not fixed in one subtype. They can shift between these states, moving from a more treatable form to a more resistant one. This flexibility is known as cancer cell plasticity. The Role of GATA6 in Tumor Behavior The research team focused on a gene called GATA6, which helps maintain pancreatic cancer cells in the more structured and less aggressive classical state. When GATA6 levels are high, tumors tend to grow in a more organized way and are more likely to respond to chemotherapy. When GATA6 levels fall, cells lose that structure, become more aggressive, and are harder to treat. Professor David Virshup of Duke-NUS's Programme in Cancer & Stem Cell Biology, the study's lead author, said: "We have known that pancreatic cancer cells can switch between these two states. What we didn't understand was the mechanism driving that switch. By identifying the pathway that suppresses GATA6, we now have a clearer picture of how tumors become resistant -- and potentially how to reverse that process." KRAS and ERK Pathway Drive the Switch The researchers traced the switch to a chain of signals inside pancreatic cancer cells. A gene called KRAS, which is mutated in nearly all pancreatic cancers, sends constant growth signals that drive tumor development. KRAS passes these signals through a partner protein known as ERK, which relays the instructions further inside the cell. When the ERK pathway becomes highly active, it protects another protein that interferes with the production of GATA6. As GATA6 levels drop, cancer cells lose their organized structure, shift toward the more aggressive basal state, and become much less responsive to chemotherapy. Using genetic screening, molecular analysis in cancer cells, and drug treatments, the team demonstrated that blocking the KRAS and ERK pathway lifts this suppression. When that happens, GATA6 levels rise again. The cancer cells then shift back toward the more organized state and regain sensitivity to chemotherapy. Combination Therapy Shows Stronger Effects The study also found that higher levels of GATA6 on their own made pancreatic cancer cells more responsive to treatment. When drugs that inhibit the KRAS and ERK pathway were combined with standard chemotherapy, the anti cancer effects were stronger than with either approach alone. However, this enhanced benefit occurred only when GATA6 was present, highlighting its central role in determining w