PAX5 and pulmonary arterial hypertension: Cytology biomarkers were positive for CD20, CD45, and PAX5. A trans-thoracic echocardiogram (TTE) was obtained prior to chemotherapy initiation to establish a baseline for cardiac function, which showed an ejection fraction (EF) of 45-50%, right ventricle volume overload and dilation, and pulmonary hypertension.