저자는 MTX투여가 백혈구염색체에 미치는 영향을 조사하기 위해 Moorhead등의 방법을 사용하여 변이에 대한 조사를 시행한 바 MTX투여종료 2주후의 염색체소견은 거의 정상과 비슷한 경향을 보였다.

Attempt has been made to study the type, frequency, and distribution pattern of the chromosome aberration induced by MTX, and the relationship of MTX dosage to the incidence of chromosome aberrations in human leucocytes. The peripheral blood leucocytes were cultured by the method of Moorhead et al. with a slight modification. In a preliminary study, the human blood leucocytes were cultured in vitro for 72 hours obtained from a healthy woman and a patient of gydatidiform mole without previous admin- istration of cytostatic agent or irradiation. Twenty-four hours before fixation, MTX(0.1-100 ㎍/ml) was added to the culture media. The data obtained in this study indicated that MTX added directly to the culture media in vitro did not cause any significant chromosomal damage. In an in vivo study, 25 sets of leucocyte culture from 5 patients of hydatidiform mole and 3 patients of choriocarcinoma were observed before and after the administration of MTX of varying doses. Upon chromosome analysis, 5 sets of leucocyte culture before administration of MTX and 20 sets after administration showed cells of good quality containing a sufficient number of chromosomes in metaphase. The following results were obtained; 1. The frequency of appearance of aneuploid cells was slightly higher in the treated series than the untreated control. 2. Chromatid and chromosome gaps and breaks appeared in 7.63% of cells in the treated series whereas it was 3.75% in the controls, indicating the significant difference between the treated and untreated series. 3. If all abnormalities are counted, including chromatid and chromosome gaps or breaks, fragments, and other abnormal chromosomes, 9.64% of the cells were involved in the treated series, and 3.75% in the controls. 4. The majority of chromosome defects was found among A and C groups of chromosomes in the MTX series. 5. Abnormal chromosomes such as dicentric chromosomes, ring chromosomes, fragments and deletions were found in the treated series, but not in the controls. 6. It was noticed that the incidence of chromosome aberrations in MTX therapy was highest at a certain range of dose(15mg-65mg), but it appeared to decrease as the dose increased. 7. Most of the chromosomal aberrations induced by MTX have disappeared 2 weeks after the termination of its administration.