Alveolar soft-part sarcoma (ASPS) is an exceedingly rare entity. We previously reported on a series of 12 ASPS the expression of PD-1/PD-L1 and lymphocytic infiltrates. PD-L1 staining was positive in 50% of the cases, suggesting a role for immunomodulatory interventions. We now enlarge the series and explore the expression of immune-related genes with the HTG EdgeSeq System and analyze their possible prognostic role.
Patients (pts) diagnosed with ASPS from Dec 1994 to Jul 2016 were reviewed. Clinical characteristics and outcome were collected. Immunohistochemical expression was tested on archived Formalin-Fixed Paraffin-Embedded (FFPE) blocks using PD-L1 (ab205921; Abcam), CD8 (ab4055; Abcam) antibodies. An ImmunOncology (IO) panel of 549 mRNAs was evaluated with the HTG EdgeSeq System from one 5µm FFPE section. This novel technology consists in a tissue digestion followed by a pre-hybridization with specific probes using quantitative nuclease protection assay (qNPA) and quantified by a standard RNA-seq protocol in a NGS sequencer.
We identified 16 ASPS pts: median age 23y (6-62), M/F=5/11. Stage localized/metastatic in 11/5. With a median FU of 91 mos (4-151), 6/11 pts (54%) relapsed, with a median RFS of 19 mos (95% CI 1-75) and 2 pts died. PD-L1 was pos in tumor in 10/16 (62%) pts. HTG showed differential expression of immune-related genes according to stage (localized vs metastatic) in MNDA (log2 fold change: -3.01, p
PD-L1 is expressed in more than a half of ASPS of our series. Differential expression in immune-associated genes suggest an immune related gene profile on this entity with clinical and pathological implications. Further exploration of immune-modulation in ASPS is ongoing.
Clinical trial identification
Legal entity responsible for the study
Spanish Group for Research on Sarcoma
Spanish Group for Research on Sarcoma (GEIS).
All authors have declared no conflicts of interest.