VAV1 and peripheral T-cell lymphoma, not otherwise specified: The presence of the Vav1-Myo1f fusion protein (where the C-terminal SH3 domain of Vav1 is replaced by the SH3 of Myo1f) was recently reported in peripheral T-cell lymphomas (PTLC), a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis.