leukaemia or leukemia is a group of blood cancers which mostly begin from the bone marrow and lead to production of several abnormal blood cells called leukemia cells [1]. Bleeding, bone pain, fatigue, fever, vulnerability to infections are main symptoms of leukemia. Besides of rare types of leukemia, four most common and most lethal types of leukemia are included acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) [2]. These four major types account for 85% of all leukemia. CLL is the most common, but AML accounts for ~ 42% of all leukemia deaths. Most common type of cancer in children, is acute lymphoblastic type, on the other hand more than 90% of all adult subjects of leukemia, are diagnosed for CLL and AML [3]. Worldwide prevalence of leukemia is approximately 2.43 million (95% UI 2.19 million to 2.59 million) with an age-standardized prevalence rate (ASPR) of 32.26 (95% UI 29.02 to 34.61) per 100,000 population with about the 400,000 death per year all around the world. Diagnosis of leukemia is typically is based on clinical symptoms, blood tests, bone marrow biopsy and cytogenetic examinations [4].
While the etiology of leukemia is not completely clarified, a combination of heritable genetic factors including mutations and chromosomal abnormalities like Down syndrome and epigenetic changer environmental factors such as smoking, radiations, several chemical compounds, prior chemotherapy, etc. are reported as risk factors of leukemia [5]. Different types of chemotherapeutic drugs, radiation therapy, targeted therapy, and bone marrow transplant, alone or in combination with each other are currently using for treatment of leukemia [6]. In addition, the Immunotherapy which prompts the immune system to identify and destroy cancerous cells is most novel treatment for leukemia. Despite of improvement in treatment success in the developed world, Five-year survival rate is lower than 65% in the United States and about 30–40% worldwide.
This disappointing survival rate of leukemia As well as considerable rate of resistance to chemotherapy, side effects of radiation and specificity of immunotherapy that made it unavailable for many cases based on their molecular testes results, has inspired much work on the development of new treatment methods. During last decades, several studies have revealed novel insights to treatment of leukemia. These treatments should be tested in animal models, and that’s' why the impact of animal models of cancer on leukemia research is very important [7].
Opium is the dried latex obtained from the seed capsules of the "Papaver Somniferum" or opium poppy which has been a source of Morphinan-based painkillers with risks of addiction [8]. Opium is effective in the treatment of different kind of acute and chronic pain that traditionally was used worldwide [9]. On the other hand opium abuse and opium dependence is a major social and health problem all around the world [10]. It has been reported that opium affects several mechanisms in body including the central nervous system (CNS), immune system, kidney functions, respiratory and cardiovascular systems [11, 12].
Opium effects on mRNA level of mammalian genes is mostly unclear. Opioid agents have major role in reduction of pain in cancer patients while the role of opiate use on epigenetic, immunological and hematological parameters as well as various metabolic and biological processes, in cancer is not clarified. Previous studies determined that the potential tumor-promoting, proliferation and migration effects of opiates are contradictory, and both growth-promoting and anti-tumor effects have been observed [13]. That's why that shedding light on complexity of opium role in cancer treatment processes is tremendously important.
In Present study effect of opium taper up-off treatment in a laboratory designed method to expression profiling of rat models of four most lethal types of leukemia, ALL, AML, CLL, and CML were assessed. We aimed to understand that how the orally consumption of opium in a bell shaped dose curve could altered the several gene expression patterns which were previously affected by leukemia and is this alteration may reduce the severity of the disease of not.