ADULT T-CELL LYMPHOMA / LEUKEMIA (ATL / ATLL) (HTLV-1+) : 4 clinical subtypes according to estent of disease and calcemia and prognosesref1, ref2, ref3 Epidemiology : first described in Japan in 1977; in southern Japan, ATL is the most common form of NHL. The lifetime risk of ATL is about 5% in people infected before the age of 20 yearsref; the incidence is approximately 0.1% infected individuals/year. There is a wide disparity in the mean age at diagnosis: 60 years in Japan, but 40 years in the Caribbean and Brazil; the reason for this disparity is unknown. Men are more commonly affected than womenref (approximately 1.5 : 1 male to female ratio).
Aetiology : HTLV-1 infection (identified by Gallo's group in 1980ref). Similar to EBV in Burkitt's lymphoma, HTLV-1 may not have direct oncogenic activity but contributes to a multistep process of worsening genetic instability by interfering with mitotic checkpoints or preventing DNA repairref.
Pathogenesis : Tax activates the transcription of several pro-proliferation genes (including IL-2, IL-2R, c-fos, GM-CSF, and numerous other genes that promote entry into the cell cycle) by the formation of multiple complexes with p300/CBP and antagonizing the transcriptional activity of p53.
Symptoms & signs : the clinical features of ATLref are those of a NHL: malaise, fever, lymphadenopathy, hepatosplenomegaly, jaundice, drowsiness, weight loss, skin lesions, hypercalcemia, lytic bone lesions, and opportunistic infections due to the underlying immunodeficiency. Other features particularly associated with ATL are thirst and skin involvement (nodules, plaques, or a generalised papular rash)
Laboratory examinations : Therapy : the disease often responds initially to standard chemotherapeutic regimens, but early relapse is common, and the disease typically becomes refractory to further chemotherapy after 2-6 months. Prognosis : survival is poor with median survivals of 6.2 months for acute leukemia and 10.2 months for lymphomaref. The chronic and particularly the smoldering subtypes have a longer survival but can transform into the more acute forms. Poor performance status, high LDH, age above 40 years, tumor bulk, and hypercalcemia are adverse prognostic factorsref. Aneuploidy and multiple chromosomal breaks are associated with an aggressive courseref. Ongoing genetic abnormalities, including defective HTLV-1 integration and deletion of tumor suppressor genes p15INK4B and p16INK4A, are associated with a worse prognosisref.

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