SDC1 and Miyoshi myopathy: In this context, while there are some fractions of MM cells that do not express CD138 or express it at low levels, which may impact the efficacy of antigen-based molecules, the fact remains that such therapies may increase the chances of thorough eradication of all malignant clones in more aggressive stages of MM disease, as these are characterized by higher levels of CD138, as evidenced by higher serum levels in these patients.