Skip to main content

Table 5 MTX sensitivity and accumulation of MTX polyglutamates in relation to cytogenetic abnormalities

From: Methotrexate resistance in relation to treatment outcome in childhood acute lymphoblastic leukemia

  

TSIA cont.

TSIA short

MTX-Glu1–6

MTX-Glu4–6

Normal cytogenetics

N

16

23

18

17

Median (range)

0.048 (0.01–0.71)

0.28 (0.16–2.84)

2102 (436–4240)

1514 (209–3190)

MLL-rearranged

N

8

6

4

3

Median (range)

0.06 (0.03–0.16)

0.21 (0.16–1.33)

591 (360–1016)

350 (280–443)

P value

0.610

0.896

0.005*

0.012*

BCR-ABL

N

4

2

4

2

Median (range)

0.04 (0.03–0.28)

–

2088 (360–3721)

1630 (1212–2047)

P value

0.750

0.240

0.712

0.749

TEL-AML1

N

10

9

8

7

Median (range)

0.16 (0.06–0.37)

0.82 (0.54–11.21)

945 (290–2476)

550 (380–1152)

P value

0.023*

0.06

0.013*

0.007*

E2A-PBX1

N

3

3

1

0

Median (range)

0.14 (0.05–0.29)

0.77 (0.57–1.12)

–

–

P value

0.254

0.157

–

–

  1. First, the Kruskal–Wallis analysis of variance was used to compare all the four groups, and variables with the P value above 0.1 were further examined in detail. The Mann–Whitney U test was used to compare MTX-related variables between each subgroup of ALL patients carrying certain cytogenetic abnormality and patients displaying normal karyotype as a reference group; TSIA continuous (TSIA cont.) and short-term exposure (TSIA short) are expressed as the concentration of MTX (in μM) necessary to inhibit 50 % of the TS activity (TSI50) compared to the controls incubated without MTX (in triplicate); the concentration of MTX polyglutamates (MTX-Glu1–6 and MTX-Glu4–6) is expressed as pmol MTX-Glun/109 cells. The asterisk denotes significant (P < 0.05) associations