The present invention concerns fragments and variants of the HYD1 peptide; polynucleotides encoding the peptides; host cells genetically modified with the polynucleotides; vectors comprising the polynucleotides; compositions containing these peptides, polynucleotides, vectors, or host cells; and methods of using the peptides, polynucleotides, vectors, and host cells as inhibitors of aberrant cell growth in vitro or in vivo, e.g., as anti-cancer agents for treatment of cancer, such as myeloma. The present invention further includes a method of increasing the efficacy of chemotherapy and radiation therapy, comprising administering an agent that binds .beta.1 integrin to a patient in need thereof. In one embodiment, the .beta.1 integrin binding agent is the HYD1 peptide, or a functional fragment or variant thereof. In another aspect, the invention pertains to a composition (an adhesion trap) comprising a substrate (also referred to as a surface or support) with a HYD1 peptide, or fragment or variant thereof, immobilized to the substrate, and a method of removing circulating tumor cells (CTC) from blood by contacting a subject's blood with the immobilized peptide. Another aspect of the invention concerns a method of identifying modulators of peptide binding. Another aspect of the invention concerns a method for detecting CTC.