I was reading up Kaposi sarcoma and Robbins Pathology says,
..many features suggest that KS is not a malignant tumor despite the ominous name ...spindle cells in many KS lesions are polyclonal or oligoclonal
This is also seen in multinodular goiter where the lesions are polyclonal, but some monoclonal nodules are found.
My question is, how are these determined? By sequencing, is it not that, in cancerous growth there are myriad mutations, how can you map whether the mutations present are due to monoclonal expansion or polyclonal expansion? In non cancerous growths, wouldn't all cells have the same genotype?
Polyclonal and monoclonal expansion in B-cells is clear to me since a polyclonal lineage would have different vdj recombs while monoclonal would have the same. Here also, is it decided by genomic sequencing or the Ig sequence?