Overview
Tumour M2-PK, also known as PKM2, is the dimeric form of the pyruvate kinase isoenzyme type M2. It is a key enzyme involved in tumour metabolism and glycolysis. Tumour M2-PK is overexpressed in many cancers and reflects altered energy metabolism seen in malignant cells. Unlike organ-specific tumour markers, Tumour M2-PK can be elevated in multiple tumour types and is therefore considered a broad tumour marker
Tumour M2-PK plays a central role in the Warburg effect, where cancer cells rely on increased glycolysis for energy production even in the presence of oxygen. This metabolic shift supports rapid cell growth and proliferation.
Symptoms
Tumour M2-PK itself does not cause symptoms. Symptoms depend on the type, location, and stage of the underlying malignancy. Many patients may remain asymptomatic in early stages of cancer.
As disease progresses, symptoms may include unexplained weight loss, fatigue, loss of appetite, anemia, abdominal discomfort, altered bowel habits, or bleeding depending on the affected organ. In colorectal cancer, patients may present with changes in stool pattern, blood in stool, or abdominal pain.
Advanced disease may be associated with systemic symptoms such as weakness, pain, or signs of metastasis.
Causes
Elevated Tumour M2-PK levels are caused by increased expression of the dimeric PKM2 enzyme in cancer cells. This occurs due to metabolic reprogramming that favors rapid energy production and biomass synthesis.
Tumour cells shift from the active tetrameric form of pyruvate kinase to the less active dimeric form. This allows accumulation of metabolic intermediates required for tumour growth and division.
Increased levels are seen in several cancers including colorectal, pancreatic, gastric, oesophageal, lung cancer, cholangiocarcinoma, and renal cell carcinoma.
Risk Factors
Risk factors for elevated Tumour M2-PK reflect general cancer risk factors. These include increasing age, genetic predisposition, family history of malignancy, and chronic inflammatory conditions.
Lifestyle factors such as smoking, alcohol consumption, obesity, poor diet, and physical inactivity increase cancer risk and indirectly increase the likelihood of elevated Tumour M2-PK.
Chronic gastrointestinal conditions, colorectal polyps, and long-standing inflammatory bowel disease increase the risk of colorectal cancer, where Tumour M2-PK is commonly used as a marker.
Prevention
There is no specific prevention for Tumour M2-PK elevation, as it reflects underlying malignancy. Cancer prevention strategies help reduce risk indirectly.
Lifestyle modification including balanced diet, regular physical activity, avoidance of tobacco and excessive alcohol, and weight control reduce overall cancer risk.
Early screening and timely testing using stool or blood samples help detect malignancies at an early stage. Regular follow-up and monitoring of Tumour M2-PK levels support assessment of treatment response and disease progression.
