667C>T and 1298A>C polymorphisms of MTHFR do not predict response to methotrexate in patients with gestational trophoblastic neoplasia

ABCB1 and SLCO1B1 gene polymorphisms predict methotrexate-resistant for low-risk gestational trophoblastic neoplasia

Aim: The aim of this study was to explore the effects of ABCB1 and SLCO1B1 gene polymorphisms and the methotrexate (MTX) treatment response in patients with low-risk gestational trophoblastic neoplasia (GTN). Materials & methods: Low-risk GTN patients who received MTX as a first-line single agent were enrolled. DNA was extracted from peripheral blood samples from 18 patients and assessed for ABCB1 C3435T and SLCO1B1 T521C. Results: ABCB1 C3435T and SLCO1B1 T521C polymorphisms were not associated with the MTX response or toxicity in Thai patients Conclusion: The selected ABCB1 and SLCO1B1 polymorphism do not predict the risk of MTX resistance in low-risk GTN.

Presence of the methylenetetrahydrofolate reductase gene polymorphism MTHFR C677T in molar tissue but not maternal blood predicts failure of methotrexate treatment for low-risk gestational trophoblastic neoplasia

Gestational trophoblastic neoplasia (GTN) is a rare tumor, and its genomic constitution is different from the maternal genome because of its gestational origin. Methotrexate (MTX) is a standard chemotherapeutic agent for low-risk GTN. An association between polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene and MTX treatment outcome has been reported in various diseases. Thus, we examined the association between clinical outcome and MTHFR polymorphisms in both tumor and blood DNA of low-risk GTN patients. MTHFR C677T (rs1801133) and A1298C (rs1801131) were genotyped using high-resolution melting assays in 62 Japanese low-risk GTN patients and in 52 antecedent molar tissues. We compared the genotypes of MTHFR polymorphisms with the clinical outcome of 5-day MTX treatment. Twenty-five patients entered remission and 37 patients developed drug resistance or adverse effects that necessitated a drug change. The MTHFR 677T allele in molar tissue was significantly related to the need for drug change (P=0.006; odds ratio [OR], 3.13; 95% confidence interval [CI], 1.31-7.49), in contrast to MTHFR 1298C (P=0.18; OR, 0.63; 95% CI, 0.32-1.25). The MTHFR 677T and 1298C alleles obtained from patients' blood DNA were not related to MTX treatment outcome (P=0.49; OR 1.31; 95% CI, 0.61-2.91 and P=0.10; OR 0.52; 95% CI, 0.22-1.15, respectively). These data demonstrate for the first time that the genotype of MTHFR 677TT in molar tissue is associated with ineffective MTX treatment in Japanese low-risk GTN patients.

The effect of parental 5,10-methylenetetrahydrofolate reductase 677C/T and 1298A/C gene polymorphisms on response to single-dose methotrexate in tubal ectopic pregnancy

OBJECT

The aim of this study was to assess the effect of parental 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms (677C/T and 1298A/C) on response to single-dose methotrexate (MTX) treatment in tubal ectopic pregnancy (TEP).

MATERIALS AND METHODS

In this prospective cohort study, cases with unruptured TEPs were grouped into two according to their response to single-dose MTX treatment (Group 1: responsive, n:88; Group 2: unresponsive, n:21). The groups were compared with regard to baseline demographic and clinical parameters. As a main outcome measure, the independent effects of parental MTHFR gene polymorphisms on response to single dose MTX treatment were evaluated.

RESULTS

One hundred and nine unruptured TEP were included in the final analysis. The mean maternal age was 29.30 ± 5.21 years, gravity 2 (min-max: 1-5), parity 1 (min-max: 0-4). The median serum beta-human chorionic gonadotropin (β-hCG) was 1403.35 MI/I (Q₁-Q₃: 517-2564). The overall response rate was 81% (88/109). The groups were similar with respect to basic baseline demographic data and serum β-hCG level. Binary logistic regression analysis showed that the presence of parental MTHFR677C/T and 1298A/C polymorphism were not independent factor predicting treatment success (p > 0.05). The only independent factor for resistance to single dose MTX was the previous TEP (OR: 4.47 (1.18-16.9)).

CONCLUSION

Parental MTHFR 677C/T and 1298A/C mutations do not predict the outcome of single dose intramuscular MTX treatment in unruptured TEP.

A case of recurrent pancytopenia in a patient with acute promyelocytic leukemia on maintenance chemotherapy and concomitant methyltetrahydrofolate reductase and thiopurine S-methyltransferase mutation - review of literature

Pharmacogenetics is a study of how genetic variation of an individual affects the drug response. We report a case of recurrent pancytopenia resulting from maintenance chemotherapy in a patient with acute promyelocytic leukemia and two pharmacogenetic mutations, namely, methylene tetrahydrofolate reductase C677T homozygous mutation and thiopurine methyltransferase mutation.

Methotrexate pharmacogenetics in rheumatoid arthritis: a status report

Methotrexate (MTX), an antifolate drug, is the first-line disease-modifying agent for the treatment of rheumatoid arthritis (RA) worldwide. MTX has excellent long-term efficacy, tolerability and safety. Early initiation of MTX in patients with RA controls joint destruction and slows progression of disease. However, the clinical response to MTX and frequency of adverse effects from the drug exhibit marked interpatient variability. Over the past decade, there has been a quest to identify genetic markers that reliably predict MTX efficacy and toxicity and help optimize MTX therapy in RA; that is, the field of MTX pharmacogenetics. This review will summarize key pharmacogenetic studies examining SNPs in the genes encoding enzymes in the MTX cellular pathway and their association with MTX response in RA. As evident from this review, MTX pharmacogenetics in RA remains a muddled field, mostly due to inconsistent results from several small underpowered studies.