Haematological and Solid Tumours
Cancers are caused by malignant tumours formed by an abnormal growth of cells and tissue leading to organ failure. They fall into two categories: solid and haemtological cancers.
Solid Tumours
Solid tumors are neoplasms (new growth of cells) or lesions (damage of anatomic structures or disturbance of physiological functions) formed by an abnormal growth of body tissue cells other than blood, bone marrow or lymphatic cells. A solid tumour consists of an abnormal mass of cells which may stem from different tissue types such as liver, colon, breast, or lung, and which initially grows in the organ of its cellular origin. However, such cancers may spread to other organs through metastatic tumor growth in advanced stages of the disease.
Hematological Tumours
In contrast, hematological tumors are cancer types affecting blood, bone marrow, and lymph nodes. Hematological tumours may derive from either of the two major blood cell lineages: myeloid and lymphoid cell lines. The myeloid cell line normally produces granulocytes, erythrocytes, thrombocytes, macrophages, and mast cells, whereas the lymphoid cell line produces B, T, NK and plasma cells. Lymphomas (e.g. Hodgkin's Lymphoma), lymphocytic leukemias, and myeloma are derived from the lymphoid line, while acute and chronic myelogenous leukemia (AML, CML), myelodysplastic syndromes and myeloproliferative diseases are myeloid in origin. As blood, bone marrow, and lymph nodes are intimately connected through the immune system, a disease affecting one haematological system may affect the two others as well.