Multiple Myeloma in Asia
Multiple myeloma (MM) is one of the most common hematologic malignancies, with 114,252 new cases and 80,119 deaths worldwide annually in 2012, comprising 0.8% and 1% of all cancers, respectively. Its incidence is known to vary by ethnicity, with Asians showing a relatively lower incidence than Caucasians by IARC data as well as US SEER data even within a country.  Although the incidence is lower, the actual number of new cases of multiple myeloma in Asia (35,828) was higher than that of North America (31,613) in 2012 because of its huge population.
We do not know exactly why Asian people have lower susceptibility to multiple myeloma. However, there are few reports reporting genetic polymorphism is related to it. [2-5]
Moreover, recent reports have suggested that the incidence of multiple myeloma is increasing in Asian countries, including Korea, Taiwan, and Thailand [6-8]. The reasons of this increase are speculated to be related to rapid industrialization and increased life span, which are common trends among Asian countries. Aging is especially related to the MGUS incidence, from which active MM develops.
Recent studies from several Asian countries showed substantial increase of MGUS with aging. [9-12]. For example, Park et al.  reported that, among 1,118 elderly (age ≥ 65 years) members of an urban Korean population, the age- and gender-adjusted MGUS prevalence was 3.3% , which is only slightly lower than the Western data. A subsequent Korean study showed that the natural clinical course of MGUS, including the rate of progression to multiple myeloma in Korea (1%/year), is similar to that in Western countries .
There have been reports describing the clinical profiles [14–16] as well as the cytogenetic characteristics [17–19] of MM in Asia, with some studies revealing unique findings in their national cohorts. Also, there have been reports describing unique drug toxicity profiles such as interstitial pneumonitis among Japanese bortezomib users [20,21], as well as lower incidence of thromboembolism among thalidomide users in some Asian countries, even without antithrombotic prophylaxis, strongly suggesting differences in pharmacogenomics [22,23].
Although several studies on the clinical features of multiple myeloma in Asian countries have been published, all of them were nationwide studies that did not include a variety of Asian ethnicities and did not incorporate recent changes in epidemiology and medical practices.
Recognizing the need for Asian multinational studies, the Asian Myeloma Network (AMN) was launched in March 2011 under the auspices of the International Myeloma Foundation (IMF) with the participation of seven countries and regions, which already had national myeloma study groups at the time: China, Hong Kong, Japan, Korea, Singapore, Taiwan, and Thailand.
Our first question was whether multiple myeloma in Asia has characteristics that differ from its presentation in Western countries as non-Hodgkin lymphoma in Asia has shown different subtype distribution. As our first project, we conducted a multinational study to define the clinical characteristics of MM in Asian countries. 
The conclusion was that multiple myeloma in Asia is not different from that of Western countries in terms of clinical and cytogenetic characteristics even though there are some minor cytogenetics characteristics observed in certain country that need to be elucidated in future studies.  This simple conclusion is very important because there are many ongoing studies on a global scale, especially novel new drugs, in which the participation from Asia is rapidly increasing recently.
Although Asian countries have limited accessibility, or availability, or approval, or affordability of novel drugs in general, each individual country has its own situations and barriers. Many of them are trying to set their standard for the treatment. 
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