Angiogenesis extent and macrophage density increase simultaneously with pathological progression in B-cell non-Hodgkin's lymphomas

The relationship between angiogenesis and the immune response in carcinogenesis and the progression of malignant disease

Recent studies have demonstrated that angiogenesis and suppressed cell-mediated immunity (CMI) play a central role in the pathogenesis of malignant disease facilitating tumour growth, invasion and metastasis. In the majority of tumours, the malignant process is preceded by a pathological condition or exposure to an irritant which itself is associated with the induction of angiogenesis and/or suppressed CMI. These include: cigarette smoking, chronic bronchitis and lung cancer; chronic oesophagitis and oesophageal cancer; chronic viral infections such as human papilloma virus and ano-genital cancers, chronic hepatitis B and C and hepatocellular carcinoma, and Epstein-Barr virus (EBV) and lymphomas; chronic inflammatory conditions such as Crohn's disease and ulcerative colitis and colorectal cancer; asbestos exposure and mesothelioma and excessive sunlight exposure/sunburn and malignant melanoma. Chronic exposure to growth factors (insulin-like growth factor-I in acromegaly), mutations in tumour suppressor genes (TP53 in Li Fraumeni syndrome) and long-term exposure to immunosuppressive agents (cyclosporin A) may also give rise to similar environments and are associated with the development of a range of solid tumours. The increased blood supply would facilitate the development and proliferation of an abnormal clone or clones of cells arising as the result of: (a) an inherited genetic abnormality; and/or (b) acquired somatic mutations, the latter due to local production and/or enhanced delivery of carcinogens and mutagenic growth factors. With progressive detrimental mutations and growth-induced tumour hypoxia, the transformed cell, to a lesser or greater extent, may amplify the angiogenic process and CMI suppression, thereby facilitating further tumour growth and metastasis. There is accumulating evidence that long-term treatment with cyclo-oxygenase inhibitors (aspirin and indomethacin), cytokines such as interferon-alpha, anti-oestrogens (tamoxifen and raloxifene) and captopril significantly reduces the incidence of solid tumours such as breast and colorectal cancer. These agents are anti-angiogenic and, in the case of aspirin, indomethacin and interferon-alpha have proven immunomodulatory effects. Collectively these observations indicate that angiogenesis and suppressed CMI play a central role in the development and progression of malignant disease.

A High Pretreatment Serum Basic Fibroblast Growth Factor Concentration Is an Independent Predictor of Poor Prognosis in Non-Hodgkin’s Lymphoma

Basic fibroblast growth factor (bFGF) is a secreted multifunctional cytokine and a potent stimulator of angiogenesis in vivo. Elevated bFGF concentrations have been detected in the serum and urine of cancer patients. We measured bFGF by enzyme-linked immunosorbent assay from sera taken from 160 non-Hodgkin’s lymphoma (NHL) patients before treatment and stored at −20°C. The patients had been observed for at least 5 years or until death. Serum bFGF concentrations (S-bFGF) ranged from undetectable to 34.7 pg/mL (median, 3.3 pg/mL). S-bFGF was detectable with a similar frequency in all subtypes of NHL. A high pretreatment S-bFGF was associated with poor overall survival. The 5-year survival rate of the patients within the highest quartile of S-bFGF concentrations (S-bFGF = 5.5 pg/mL) was only 39%, in contrast to a 60% survival rate of the patients with lower S-bFGF (P = .019). A high S-bFGF (within the highest quartile) was associated with poor outcome also in large-cell diffuse and immunoblastic lymphomas (5-year survival rates of 28% v56%, respectively; P = .027), which was the largest histologic subgroup (n = 66) within the series. In multivariate analyses, S-bFGF was an independent prognostic factor, both when the highest quartile was used as a cut-off value (P = .0079) and when S-bFGF and the other parameters were entered into the model as continuous variables (P = .024). In the multivariate analyses, S-bFGF had a noticeably stronger prognostic value than serum lactate dehydrogenase and the number of extranodal tumor sites, both of which are currently included as components in the International Prognostic Index.

The role of the vascular phase in solid tumor growth: a historical review

Angiogenesis is a biological process by which new capillaries are formed from pre-existing vessels. It occurs in both physiological conditions such as embryo development, cyclically in the female genital system and during wound repair, and pathological conditions, such as arthritis, diabetic retinopathy and tumors. In solid tumor growth, a specific critical turning point is the transition from the avascular to the vascular phase. Having developed an intrinsic vascular network, the neoplastic mass is able to grow indefinitely (unlike all the other forms, tumor angiogenesis is not limited in time) both in situ and at distant sites (metastasis) in so far as an intrinsic vascular network enables its cells to enter the vascular bed and colonize other organs. Tumor angiogenesis depends mainly on the release by neoplastic cells of growth factors specific for endothelial cells and able to stimulate growth of the host's blood vessels. This review describes its history as traced by the main contributions to the international medical literature and their contents. The specific new paradigm discussed here has been gaining general approval and considerable confirmation, thanks to its possible applications, as recently highlighted by the introduction of anti-angiogenic substances in adjuvant tumor management.