The investigators found that CD30 expression was maintained in tumor samples from patients with BV-refractory HL, as well as in two independent BV-resistant cell lines, both of which were found to have upregulation of the multidrug resistance gene MDR1, suggesting that BV resistance may be mediated in part by increased MDR1 activity rather than CD30 loss [109]. This evidence concerns the gene TNFRSF8 and bacterial vaginosis.