Pembrolizumab with external radiation therapy effectively controlled TMB-high unresectable recurrent parathyroid cancer: a case report with review of literature.

Parathyroid cancer (PC) is extremely resistant to chemotherapy and radiotherapy (RT), but hormonally functional by producing excessive parathyroid hormone (PTH), causing remarkable hypercalcemia even in biochemical disease recurrence. Accordingly, management of hypercalcemia by calcimimetics and bisphosphonates has been main treatment for unresectable PC. Here, we report a case of unresectable tumor mutational burden (TMB)-high recurrent PC that has been effectively controlled by pembrolizumab (PEM) with RT. A 48-year-old male patient, with previous history of left single parathyroidectomy for primary hyperparathyroidism, underwent surgeries for recurrent hyperparathyroidism at 47 and 48 years of age, and was pathologically diagnosed with PC. He was referred to our hospital due to persistent hypercalcemia and elevated PTH. The recurrent tumors were identified in the superior mediastinum and radically resected, then the hyperparathyroidism was improved. A FoundationOne® CDx of the specimen called TMB-high. He demonstrated recurrent hyperparathyroidism at 49 years of age, and underwent a gross curative resection. However, hyperparathyroidism achieved only insufficient improvement, indicating biochemical residual cancer cells. PEM treatment was initiated in combination with RT to the left central-lateral neck and superior mediastinum. He successfully achieved evocalcet and zoledronate withdrawal, and the PTH level improvement was continuously observed for 8 months at present, with only grade 2 subclinical hypothyroidism. Interestingly, leukocyte fraction ratios were reversed corresponding to disease improvement. A combination of PEM and RT is a promising treatment of unresectable TMB-high PC. Recent evidence on the immunomodulatory effect of RT provides the rationale for the combination of RT and PEM.

CAF-associated genes putatively representing distinct prognosis by in silico landscape of stromal components of colon cancer.

Comprehensive understanding prognostic relevance of distinct tumor microenvironment (TME) remained elusive in colon cancer. In this study, we performed in silico analysis of the stromal components of primary colon cancer, with a focus on the markers of cancer-associated fibroblasts (CAF) and tumor-associated endothelia (TAE), as well as immunological infiltrates like tumor-associated myeloid cells (TAMC) and cytotoxic T lymphocytes (CTL). The relevant CAF-associated genes (CAFG)(representing R index = 0.9 or beyond with SPARC) were selected based on stroma specificity (cancer stroma/epithelia, cS/E = 10 or beyond) and expression amounts, which were largely exhibited negative prognostic impacts. CAFG were partially shared with TAE-associated genes (TAEG)(PLAT, ANXA1, and PTRF) and TAMC-associated genes (TAMCG)(NNMT), but not with CTL-associated genes (CTLG). Intriguingly, CAFG were prognostically subclassified in order of fibrosis (representing COL5A2, COL5A1, and COL12A1) followed by exclusive TAEG and TAMCG. Prognosis was independently stratified by CD8A, a CTL marker, in the context of low expression of the strongest negative prognostic CAFG, COL8A1. CTLG were comprehensively identified as IFNG, B2M, and TLR4, in the group of low S/E, representing good prognosis. Our current in silico analysis of the micro-dissected stromal gene signatures with prognostic relevance clarified comprehensive understanding of clinical features of the TME and provides deep insights of the landscape.

Development of Organelle Replacement Therapy Using a Stearyl-Polyhistidine Peptide against Lysosomal Storage Disease Cells.

We previously reported on a polyhistidine peptide, His16 peptide, as a new cell-penetrating peptide. This peptide is anticipated to be a new carrier for drug delivery systems (DDSs) for targeting intracellular lysosomes because it can transport macromolecules (e.g., liposomes) into these organelles. In the present study, we examined the application of His16 peptide as a DDS carrier against lysosomal storage disease (LSD) cells. LSDs are metabolic disorders caused by loss of specific lysosomal enzymes. For the treatment of LSD cells, we devised a system designated organelle replacement therapy (ORT). ORT is a strategy for transporting exogenous lysosomes containing all kinds of lysosomal enzymes from normal cells into endogenous lysosomes in LSD cells using His16 peptide. To develop the ORT system, we prepared His16 peptide-modified healthy lysosomes (His16-Lyso) by insertion of a stearyl-His16 peptide into a hydrophobic region in the lysosomal membrane. His16-Lyso showed cellular uptake and localization to endogenous lysosomes in LSD cells. His16-Lyso also restored the proliferation of LSD cells, which otherwise showed slower proliferation than normal cells. These results suggested that His16-Lyso replenished deficient lysosomal enzymes in LSD cells. The results further suggest that His16-Lyso are promising candidates as a treatment tool for LSD cells and to establish a foundation for ORT.