MEK Inhibitors and Gastric Precancerous Lesions: Gastroenterology | March 2026
What Are MEK Inhibitors?
MEK inhibitors are targeted drugs that block the MAPK/ERK signalling pathway, specifically the MEK (mitogen-activated protein kinase kinase) enzyme. This pathway regulates cell proliferation, survival, and differentiation, and its abnormal activation contributes to several cancers. Drugs such as trametinib are already used in oncology (e.g., melanoma and BRAF-mutant cancers) and are now being explored for reversing early precancerous changes in tissues before cancer develops.
What Are Gastric Precancerous Lesions?
Gastric precancerous lesions are pathological changes in the stomach lining that increase the risk of gastric cancer. The most important include:
Chronic atrophic gastritis
Intestinal metaplasia (IM)
Dysplasia
These lesions often arise after long-term Helicobacter pylori infection and may progress to gastric cancer over many years.
Summary
In a phase 1 clinical trial evaluating trametinib, a MEK inhibitor, for reversing gastric precancerous lesions such as intestinal metaplasia and parietal cell atrophy. The trial suggested that short-term, low-dose MEK inhibition may improve gastric mucosal histology, indicating a potential preventive strategy against gastric cancer. However, the authors highlight important limitations. The study included only 15 patients, lacked a randomised placebo-controlled group, and focused exclusively on patients with previously resected stage I gastric cancer and prior H. pylori eradication, limiting generalizability. Additionally, histologic improvements are intermediate markers and do not prove reduced cancer risk, particularly with only 1 year of follow-up. Statistical concerns, such as a lack of adjustment for multiple comparisons, were also noted. Despite these limitations, the study represents the first human investigation of MEK inhibitors for gastric cancer prevention, providing early proof-of-concept and laying the groundwork for larger, long-term trials assessing cancer incidence as the ultimate outcome.
