**Part 2**

**NK Cell Leukemia** 

32 Novel Aspects in Acute Lymphoblastic Leukemia

Yasuda, T., Sanjo, H., Pagès, G., Kawano, Y., Karasuyama, H., Pouysségur, J., Ogata, M. &

Young, Jl., Gloeckler, RL., Silverberg, E., Horm, JW. & Miller R. (1986). Cancer incidence,

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499-508, ISSN 1074-7613.

Kurosaki, T. (2008). Erk kinases link pre-B cell receptor signaling to transcriptional events required for early B cell expansion. *Immunity*, Vol.28, No.4, (April 2008), pp.

survival, and mortality for children younger than age 15 years. *Cancer*, Vol.58,

**2** 

*Japan* 

Shoko Kobayashi *Kohseichuo Hospital* 

**Natural Killer Cell Leukemia:** 

**Diagnosis, Pathogenesis and Treatment** 

Natural Killer(NK) cell nenoplasm is heterogeneous disease group. In the latest World Health Organization(WHO) classification of tumors of hematopoietic and lymphoid tissue(2008), disease entities considered as NK cell deviation are 1) Aggressive NK cell leukemia (ANKL), 2) NK cell lymphoblastic leukemia/lymphoma, 3) Extranodal NK/T-cell lymphoma, nasal. While several NK related diseases are proposed and investigated actively, optical treatment of NK cell neoplasms remains uncertain. However, several new

Natural killer(NK) cells are the first lymphoid cells deployed in the defense against tumors and viral infection(Sun, 2010). Their activity is regulated by the interplay between inhibitory receptors, most of which recognize MHC class I molecules on target cells, and activating receptors which bind various ligands. Because NK cells originate from progenitor cells that can give rise to either NK or T cells; NK cells are phenotypically and immunologically similar to T cells. NK cells express T cell-associated markers, including CD2, cytoplasmic CD3(cCD3), CD7 and CD8, subsets of cytotoxic T cells and also express the NK-associated markers, CD16, CD56 and CD57. NK cells do not rearrange the T-cell receptor (TCR) genes. Early in development, NK-cell progenitors express no specific markers. Some markers that might be considered relatively more specific with NK progenitors, such as CD94 or CD161

Important inhibitory receptors are members of the immunoglobulin-like receptor (KIR) family as well as CD94/NKG2 heterodimers. Examples for activating receptors are NKG2D (CD314), DNAM-1 (CD226) and the well-characterized natural cytotoxicity receptors (NCRs), NKp30(CD337), NKp44 (CD336) and NKp46 (CD335). Activating receptors such as NKG2D, recognize ligands that are not usually expressed by healthy cells but rather expressed by infected cells. The inhibitory receptors of NK cells interact with specific MHC class I molecules; for example, CD94/NKG2 binds to HLA-E, and KIR binds to HLA-B. The major constituents of cytotoxic granules are perforin and

chemoagents and transplantation are now in progress.

**1. Introduction** 

**2. Natural killer cell** 

are no commonly tested.

granzyme B.

**2.1 Definition** 
