Soft Tissue Sarcoma Update, Issue 1, 2017 (Video Program)Etiology and risk factors for the development of soft tissue sarcoma (STS)
3:20 minutes.
TRANSCRIPTION:
DR POLLACK: There are a number of genetic syndromes that can predispose somebody to sarcoma. Li-Fraumeni syndrome is an important one. Retinoblastoma, adults that have had retinoblastoma as a child often will develop soft tissue sarcomas as an adult. And then there’s many other genetic syndromes that can cause soft tissue sarcoma. DR LOVE: I was interested by a couple of slides you had kind of related to the biology — (1), the simple versus complex tumor biology, and then the translocation-related sarcomas. Can you kind of go through that? DR POLLACK: Yes. So there’s so many different sarcomas that sometimes it can help to classify them in your mind. There are the very mutated genetically complex sarcomas, and those include undifferentiated pleomorphic sarcomas. And leiomyosarcoma probably falls in that camp as well. Then there are the very genetically simple translocation-associated sarcomas. Those include myxoid/round cell liposarcoma, synovial sarcoma, alveolar soft part sarcoma. And then there’s some other sarcomas that don’t really fall into either camp — for example, well/dedifferentiated liposarcoma driven through a very specific pathway, MDM2 and CDK4. It doesn’t really have a lot of mutations, although dedifferentiated liposarcoma can acquire mutations over time. So sometimes that helps me to classify these different sarcoma subtypes. DR LOVE: Any thoughts about or maybe data to look into the question of how accurate a diagnosis of sarcoma is, particularly in a community-based setting? I don't know if there are, like, second pathology opinion papers. But how often is there a major discrepancy? DR POLLACK: It’s actually quite common. It’s very important to have an experienced bone and soft tissue pathologist review the case, because almost a third of the time, pathologists that are not used to dealing with sarcoma will misclassify the sarcoma subtype, whereas there’s a very high concordance rate in experienced bone and soft tissue pathologists in classifying these sarcoma cases. DR LOVE: In terms of classifying, is it pretty much completely histopathology? Are there biomarkers? Are there clinical syndromes? Is it just histology? DR POLLACK: No. There are definitely markers that will classify sarcomas into different subtypes. For example, in part it has to do with morphology. But, for example, there are certain immunohistochemical stains that will classify different sarcomas as different types. For example, leiomyosarcoma will have smooth muscle actin. And then in terms of translocations, there are FISH tests to say that the synovial sarcoma has, indeed, the SYTSXX fusion gene or myxoid/round cell liposarcoma has its fusion gene. So there are, in some cases, very specific tests that you can use to confirm the diagnosis. |