Recently, however,  the surface antigen CD319 (SLAMF7) was discovered to be considerably more stable and allows robust isolation of malignant plasma cells from delayed or even cryopreserved samples.The prognosis varies widely depending upon various risk factors. The Mayo Clinic has developed a risk-stratification model termed Mayo Stratification for Myeloma and Risk-adapted Therapy (mSMART), which divides people into high-risk and standard-risk categories. People with deletion of chromosome 13 or hypodiploidy by conventional cytogenetics, t(4;14), t(14;16), t(14;20) or 17p- by molecular genetic studies, or with a high plasma cell labeling index (3% or more) are considered to have high-risk myeloma. Medical imaging
The diagnostic examination of a person with suspected multiple myeloma typically includes a skeletal survey. This is a series of X-rays of the skull, axial skeleton, and proximal long bones. Myeloma activity sometimes appears as "lytic lesions" (with local disappearance of normal bone due to resorption). And on the skull X-ray as "punched-out lesions" (raindrop skull). Lesions may also be sclerotic, which is seen as radiodense. Overall, the radiodensity of myeloma is between −30 and 120 Hounsfield units (HU). Magnetic resonance imaging is more sensitive than simple X-rays in the detection of lytic lesions, and may supersede a skeletal survey, especially when vertebral disease is suspected. Occasionally, a CT scan is performed to measure the size of soft-tissue plasmacytomas. Bone scans are typically not of any additional value in the workup of people with myeloma (no new bone formation; lytic lesions not well visualized on bone scan).
If it is determined that a tumor is overexpressing the erbB2 oncogene and the patient has no significant pre-existing heart disease, then a patient is eligible for treatment with trastuzumab. It is surprising that although trastuzumab has great affinity for HER2 and high doses can be administered (because of its low toxicity), 70% of HER2+ patients do not respond to treatment. In fact resistance to the treatment develops rapidly, in virtually all patients. A mechanism of resistance involves failure to downregulate p27 (Kip1)   as well as suppressing p27 translocation to the nucleus in breast cancer, enabling cdk2 to induce cell proliferation.In May 2021, the FDA approved pembrolizumab in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy for the first-line treatment of people with locally advanced unresectable or metastatic HER2 positive gastric or gastroesophageal junction (GEJ) adenocarcinoma. Duration of treatment
The optimal duration of add-on trastuzumab treatment after surgery for early breast cancer is unknown. One year of treatment is generally accepted based on clinical trial evidence that demonstrated the superiority of one-year treatment over none. However, a small Finnish trial also showed similar improvement with nine weeks of treatment over no therapy. Because of the lack of direct head-to-head comparison in clinical trials, it is unknown whether a shorter duration of treatment may be just as effective (with fewer side effects) than the accepted practice of treatment for one year. Debate about treatment duration has become a relevant issue for many public health policy makers because administering trastuzumab for a year is very expensive.