OS curves for validation samples. (A) OS curves for validation samples-A according to iATL-PI. iATL-PI was calculated as 1.51 × log₁₀ (sIL2R [U/mL]). Patients were stratified according to the following 3 risk groups: low risk, score ≤4.62; intermediate risk, 4.62 < score ≤ 5.79; and high risk, score >5.79. (B) OS curves for validation samples-A according to simplified iATL-PI. Patients were stratified according to the following 3 risk groups: low risk, sIL-2R ≤1000; intermediate risk, 1000 < sIL-2R ≤ 6000; and high risk, sIL-2R > 6000. (C) OS curves for validation samples-B according to Shimoyama’s classification, including the favorable/unfavorable chronic types and smoldering type. The sIL-2R level by picogram per milliliter may be converted to units per milliliter, using the formula: value (pg/mL) × 0.113.