Targeting CD73 to Overcomes Resistance to First-Generation EGFR Tyrosine Kinase Inhibitors in Non–Small Cell Lung Cancer / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#In patients with epidermal growth factor receptor (EGFR)-mutant non–small cell lung cancer (NSCLC), EGFR tyrosine kinase inhibitors (TKIs) improve response rate and survival. However, most patients eventually develop resistance. This study aimed to identify the role of CD73 in EGFR-mutant NSCLC and explore whether CD73 inhibition may serve as a therapeutic strategy in NSCLC patients with acquired resistance to EGFR-TKIs. @*Materials and Methods@#We evaluated the prognostic role of CD73 expression in EGFR-mutant NSCLC using tumor samples from a single institution. We silenced CD73 in EGFR-TKI–resistant cell lines using short hairpin RNA (shRNA) targeting CD73 and also transfected a vector alone as a negative control. Using these cell lines, cell proliferation and viability assays, immunoblot assays, cell cycle analysis, colony-forming assays, flow cytometry, and apoptosis analysis were performed. @*Results@#High expression of CD73 was associated with shorter survival in patients with metastatic EGFR-mutant NSCLC treated with first-generation EGFR-TKI. CD73 inhibition synergistically inhibited cell viability with first-generation EGFR-TKI treatment compared with the negative control. When CD73 inhibition and EGFR-TKI treatment were combined, G0/G1 cell cycle arrest was induced through the regulation of p21 and cyclin D1. In addition, the apoptosis rate was increased in CD73 shRNA-transfected cells treated with EGFR-TKI. @*Conclusion@#High expression of CD73 adversely affects the survival of patients with EGFR-mutant NSCLC. The study demonstrated that inhibiting CD73 in EGFR-TKI–resistant cell lines resulted in increased apoptosis and cell cycle arrest, which overcame the acquired resistance to first-generation EGFR-TKIs. Further research is needed to determine whether blocking CD73 plays a therapeutic role in EGFR-TKI–resistant patients with EGFR-mutant NSCLC.

An Autopsy Proven Case of CSF1R-mutant Adult-onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia (ALSP) with Premature Ovarian Failure

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a progressive degenerative white matter disorder caused by mutations in the tyrosine kinase domain of the CSF1R gene. ALSP is often misdiagnosed as other diseases due to its rarity and various clinical presentations such as Parkinsonism, pyramidal signs, cognitive impairment and/or psychiatric symptoms. We describe an autopsy case of ALSP with a CSF1R mutation. A 61-year-old woman presented insidious-onset gait difficulty for 12 years since her age of 49, and premature ovarian failure since her age of 35. At initial hospital visit, brain magnetic resonance imaging revealed hydrocephalus. Initially, Parkinson's syndrome was diagnosed, and she was prescribed L-dopa/carbidopa because of spasticity and rigidity of extremities, which had worsened. Subsequently, severe neuropsychiatric symptoms and cognitive impairment developed and radiologically, features of leukoencephalopathy or leukodystrophy were detected. She showed a down-hill course and died, 12 years after initial diagnosis. At autopsy, the brain showed severe symmetric atrophy of bilateral white matter, paper-thin corpus callosum, thin internal capsule, and marked hydrocephalus. Microscopically, diffuse loss of white matter, relatively preserved subcortical U-fibers, and many eosinophilic bulbous neuroaxonal spheroids were noted, but there was no calcification. Pigmented glia with brown cytoplasmic pigmentation were readily found in the white matter, which were positive for Periodic acid-Schiff, p62, and CD163 stains, but almost negative for CD68. Whole-exome and Sanger sequencing revealed a CSF1R mutation (c.2539G>A, p.Glu847Lys) which was reported in prior one ALSP case. This example demonstrates that ALSP could be associated with premature ovarian failure.

Primary Peripheral Gamma Delta T-Cell Lymphoma of the Central Nervous System: Report of a Case Involving the Intramedullary Spinal Cord and Presenting with Myelopathy

Primary central nervous system lymphoma of T-cell origin (T-PCNSL) is rare, and its clinicopathological features remain unclear. Peripheral T-cell lymphoma of γδ T-cell origin is an aggressive lymphoma mainly involving extranodal sites. Here, we report a case of γδ T-PCNSL involving the intramedullary spinal cord and presenting with paraplegia. A 75-year-old Korean woman visited the hospital complaining of back pain and lower extremity weakness. Magnetic resonance imaging revealed multifocal enhancing intramedullary nodular lesions in the thoracic and lumbar spinal cord. An enhancing nodular lesion was observed in the periventricular white matter of the lateral ventricle in the brain. There were no other abnormalities in systemic organs or skin. Laminectomy and tumor removal were performed. The tumor consisted of monomorphic, medium-to-large atypical lymphocytes with pale-to-eosinophilic cytoplasm. Immunohistochemically, the tumor cells were CD3(+), TCRβF1(-), TCRγ(+), CD30(-), CD4(-), CD8(-), CD56(+), TIA1(+), granzyme B(+), and CD103(+). Epstein-Barr virus in situ was negative. This case represents a unique T-PCNSL of γδ T-cell origin involving the spinal cord.