remission two patients complete remission unconfirmed and three patients with partial remissions these results were very good given that these patients had refractory or relapsed disease these clinical observations obtained by the inventors are a direct in vivo proof of the inventors 39 observations in their experimental system taken together the inventors have discovered several novel findings the inventors have discovered that as 2 o 3 decreased cyclin d1 the inventors further discovered that the decrease in cyclin d1 was post transcriptional the inventors moreover discovered that as 2 o 3 induced gsk 3 u03b2 and ikk activation and hence phosphorylation of cyclin d1 the inventors then showed that phosphorylated cyclin d1 was degraded in the proteasome finally the inventors have made the novel observation that oral as 2 o 3 induced a high response rate clinically in patients with refractory or relapsed mcl a cancer that over expressed cyclin d1 the present invention of using oral arsenic trioxide in suppressing cyclin d1 is an important paradigm applicable to the treatment of cancers that are dependent on cyclin d1 for proliferation survival metastasis and differentiation the following delivery systems which employ a number of routinely used pharmaceutical carriers are only representative of the many embodiments envisioned for administering the instant compositions injectable drug delivery systems include solutions suspensions gels microspheres and polymeric injectables and can comprise excipients such as solubility altering agents e g ethanol propylene glycol and sucrose and polymers e g polycaprylactones and plga 39 s implantable systems include rods and discs and can contain excipients such as plga and polycaprylactone oral delivery systems include tablets and capsules these can contain excipients such as binders e g hydroxypropylmethylcellulose polyvinyl pyrilodone other cellulosic materials and starch diluents e g lactose and other sugars.