Expression of the mitotic-arrest deficiency 2 is associated with chemotherapy resistance in ovarian serous adenocarcinoma

Mitotic-arrest deficiency 2 (MAD2) is a key component of spindle assembly checkpoint (SAC) function; SAC mediates spindle microtubule attachment to kinetochores on chromosomes and chromosomal segregation during mitosis. To determine whether MAD2 expression is associated with chemotherapy resistance in ovarian serous adenocarcinoma, we reviewed tumor samples from 41 cases of ovarian serous adenocarcinoma at Osaka City University Medical School Hospital (Osaka, Japan), 2000-2007. Of the 41 cases, 24 were recurrent and 17 were not recurrent. Expression of MAD2 was investigated in paraffin-embedded sections using a MAD2 antibody. Quantitative analysis of MAD2 expression gave mean weighted scores of 4.3 for the relapsed group and 7.2 for the relapse-free group; the expression was, thus, significantly greater in the relapse-free group compared to the relapsed group (P=0.023). When the 41 cases were classified into lowand high-expression, these classifications showed no significant difference in terms of progression-free survival (P=0.0685), however, overall survival for the low-expression group was significantly shorter than that of the high-expression group (P=0.0188). The present study implies that MAD2 expression levels can indicate sensitivity to anticancer agents, and risk for recurrence.