Metabolic micromilieu in tumours

Solid malignant tumours are characterized by a heterogeneous metabolic micromilieu with the intra-individual variability within single tumours being substantially smaller than the inter-individual differences between tumours. Despite this variability, there are some hallmarks which are characteristic for the majority of malignancies. They include hypoxia, tissue acidosis, and abnormal microcirculation. Peculiarities of the carbohydrate metabolism and specifically of glycolysis in tumours receive increasing attention in experimental and clinical research. As shown by our research with induced bioluminescence, different tumours from various entities exhibit a large spectrum of lactate accumulation. Interestingly, primary lesions with metastasis contain significantly higher amounts of lactate as compared to non-metastatic tumours. Classification into high and low lactate tumours according to the median lactate concentration in combination with a Kaplan-Meier analysis reveals that survival of patients with high lactate tumours is significantly worse than that with low lactate carcinomas. Furthermore, there is a positive correlation between tumour lactate content and radio-resistance. Conclusion: High lactate tumours are characterized by a higher degree of malignancy and therapeutic resistance.