Table 1.
Clinical and laboratory characteristics of 641 patients with primary myelofibrosis stratified by center of referral: Mayo Clinic, Rochester, MN, USA vs. University of Florence, Florence, Italy
| Variables | All patients (n = 641)a | Mayo Clinic cohort (n = 488) | University of Florence cohort (n = 153) | P-value |
|---|---|---|---|---|
| Age in years; median (range) | 63 (19–89) | 63 (22–87) | 62 (19–89) | 0.2 |
| Age >65 years; n(%) | 263 (41) | 202 (41) | 61(40) | 0.7 |
| Males (%) | 411 (64) | 310 (64) | 101 (66) | 0.6 |
| Hemoglobin <10 g/dl; n (%) | 260 (41) | 217 (45) | 43 (28) | <0.001 |
| Transfusion requiring; n (%) | 191 (30) | 156 (32) | 35 (23) | 0.03 |
| Leukocytes, x109/l; median (range) | 9 (1–219) | 9 (1–219) | 9 (2–150) | 0.7 |
| Leukocytes >25 × 109/l;n (%) | 89 (14) | 71(15) | 18 (13) | 0.6 |
| Platelets <100 × 109/l;n (%) | 122 (19) | 104 (21) | 18 (13) | 0.02 |
| Circulating blasts ≥1%; n (%) | 297 (47) | 262 (54) | 35 (24) | <0.001 |
| Circulating blasts ≥2%; n (%) | 173 (27) | 148 (30) | 25 (16) | <0.001 |
| Constitutional symptoms; n (%) | 208 (32) | 161 (33) | 47 (31) | 0.6 |
| DIPSS b risk distribution | <0.001 | |||
| High | 83 (13) | 50 (10) | 33 (22) | |
| Intermediate-2 | 242 (38) | 188 (39) | 54 (35) | |
| Intermediate-1 | 214 (33) | 176 (36) | 38 (25) | |
| Low | 102 (16) | 74 (15) | 28 (18) | |
| Driver mutations | 0.03 | |||
| JAK2; n (%) | 368 (57) | 288 (59) | 80 (53) | |
| CALR type 1/like; n (%) | 123 (19) | 99 (20) | 24 (16) | |
| CALR type 2/like; n (%) | 32 (5) | 19 (4) | 13 (8) | |
| MPL;n (%) | 46 (7) | 33 (7) | 13 (8) | |
| Triple negative; n (%) | 72 (12) | 49 (10) | 23 (15) | |
| Revised cytogenetic risk distribution c | 0.2 | |||
| Very high risk; n (%) | 43 (7) | 32 (7) | 11 (7) | |
| Unfavorable; n (%) | 94 (15) | 78 (16) | 16 (11) | |
| Favorable; n (%) | 504 (78) | 378 (77) | 126 (82) | |
| ASXL1-mutated;n (%) | 242 (38) | 188 (39) | 54 (35) | 0.5 |
| SRSF2-mutated; n (%) | 89 (14) | 70 (14) | 19 (12) | 0.5 |
| U2AF1Q157-mutated; n(%) | 50 (8) | 46 (9) | 4 (3) | 0.006 |
| EZH2-mutated; n(%) | 37 (7) | 16 (4) | 21 (14) | <0.001 |
| IDH1/2-mutated; n (%) | 23 (4) | 20 (5) | 3 (2) | 0.1 |
| MIPSS70-plus risk distribution d | 0.005 | |||
| Very high; n (%) | 76 (12) | 58 (12) | 18 (12) | |
| High; n (%) | 263 (41) | 216 (44) | 47 (31) | |
| Intermediate; n (%) | 125 (20) | 95 (20) | 30 (19) | |
| Low; n (%) | 177 (27) | 119 (24) | 58 (38) |
The values in bold indicate a significant P-value (<0.05)
ASXL1 additional sex combs like 1, SRSF2 Serine/arginine-rich splicing factor 2, U2AF1 U2small nuclear RNA auxiliary factor 1, EZH2 enhancer of zeste homolog 2, IDH1/2 isocitrate dehydrogenase 1/2, JAK2 Janus kinase 2,CALR calreticulin, MPL myeloproliferative leukemia virus oncogene
a In most instances, including all GIPSS-relevant variables, information was available in all 641 patients. In all instances of genetic risk factor analysis, a minimum of 500 informative cases was required and missing information did not exceed 10%
b DIPSS, Dynamic International Prognostic Scoring System uses five independent predictors of inferior survival: age > 65 years, hemoglobin <10 g/dl, leukocytes >25 × 109/L, circulating blasts ≥1% and constitutional symptoms (reference in the text)
c Revised cytogenetic risk stratification: “very high risk (VHR)”—single/multiple abnormalities of −7, i(17q), inv(3)/3q21, 12p−/12p11.2, 11q−/11q23, +21, or other autosomal trisomies, not including +8/+9; “favorable”—normal karyotype or sole abnormalities of 13q−, +9, 20q−, chromosome 1 translocation/duplication or sex chromosome abnormality including—Y; “unfavorable”—all other abnormalities (reference in the text)
d MIPSS70-plus, Mutation-Enhanced International Prognostic Score System for transplant-age patients uses: hemoglobin <10 g/dl, leukocytes >25 × 109/L, platelets <100 × 109/L, circulating blasts ≥2%, constitutional symptoms, absence of CALR type 1 mutation, presence of high-molecular risk mutation (e.g., ASXL1, EZH2, SRSF2, IDH1/2), presence of two or more high-molecular risk mutations and a two-tiered revised cytogenetic risk stratification where very high risk and unfavorable karyotype are grouped together as “unfavorable” (reference in the text)