Long-term survival of two patients with inoperable post-irradiation osteosarcoma treated with carbon-ion radiotherapy: a case report

BACKGROUND

Curative treatment of inoperable post-irradiation sarcoma is often challenging, especially using radiotherapy, wherein curative dose administration is difficult because the organs around the tumor have already been irradiated during the first cancer treatment. Carbon-ion radiotherapy (C-ion RT) might be useful in the treatment of post-irradiation sarcomas because it allows re-irradiation with high-dose localization properties and also demonstrates higher cytotoxic effects on radioresistant tumors compared with X-rays. This study presents the long-term survival of two patients with inoperable post-irradiation pelvic osteosarcoma treated with C-ion RT after uterine cervical cancer treatment.

CASE PRESENTATION

The durations from prior radiotherapy to the diagnosis of post-irradiation osteosarcoma were 112.8 and 172.2 months, respectively. Both patients received 70.4 Gy (relative biological effectiveness) in 16 fractions of C-ion RT, and chemotherapy was performed before and after C-ion RT. Both patients achieved a complete response 1 year after the initiation of C-ion RT. However, one patient developed single lung metastasis 12.6 months after the initiation of C-ion RT and underwent thoracoscopic lobectomy. After 63.7 and 89.0 months from the initiation of C-ion RT, respectively, the patients were alive with no evidence of local recurrence, other distant metastasis, or fatal toxicities.

CONCLUSIONS

The study findings suggest that C-ion RT is a suitable treatment option for inoperable post-irradiation osteosarcoma.

A risk factor analysis for local recurrence of bone and soft tissue sarcoma treated with carbon ion radiotherapy: A retrospective cohort study at a single institution

AIM

Carbon ion radiotherapy is well-recognized as an excellent radiation modality that is suitable for treating unresectable bone and soft-tissue sarcoma of the trunk, spine, and pelvis; however, further study is needed to improve the local control rate. The current study examined the risk factors of the local recurrence of sarcomas after carbon ion radiotherapy.

METHODS

Patients with inoperable bone and soft-tissue sarcomas treated with carbon ion radiotherapy in our institute from 2010 to 2018 were retrospectively analyzed. Among them, 87 patients were eligible for this study. We divided the instances of local recurrence into two types, in-field and out-field recurrence, and evaluated the predictors for the risk of local recurrence such as the age at the treatment, sex, histopathological diagnosis, standard uptake value on fluorodeoxyglucose positron emission tomography, and the clinical target volume for each recurrence using a Cox proportional hazards model.

RESULTS

A multivariate analysis revealed that the tumors with a post-treatment standard uptake value of more than 3.84 on positron emission tomography had a significantly high risk of in-field recurrence (hazard ratio, 3.42; p = .03). Furthermore, postoperative lesions were a risk factor for out-field recurrence (hazard ratio, 3.82; p < .01).

CONCLUSION

The current study revealed that sarcomas maintaining a high glucose metabolic activity after carbon ion radiotherapy carried a risk of in-field recurrence, and the most significant risk factor of out-field recurrence was identified to be surgery before CIRT.

Comprehensive serum and tissue microRNA profiling in dedifferentiated liposarcoma

Sarcoma is a rare cancer with several subtypes; therefore, our understanding of the pathogenesis of sarcoma is limited, and designing effective treatments is difficult. Circulating microRNAs (miRNAs), including exosomal miRNAs, have attracted attention as biomarkers in cancer. However, the roles of miRNAs and exosomes in sarcoma remain unclear. The present analysis of tissue and serum miRNA expression in osteosarcoma, Ewing's sarcoma and dedifferentiated liposarcoma (DDLPS) identified miR-1246, −4532, −4454, −619-5p and −6126 as biomarkers for DDLPS. These miRNAs were highly expressed in human DDLPS cell lines and exosomes, suggesting that they are secreted from DDLPS tissues. The present results suggested that specific miRNAs may be used as biomarkers for early diagnosis or treatment targets in DDLPS.

Rectal dose-sparing effect with bioabsorbable spacer placement in carbon ion radiotherapy for sacral chordoma: dosimetric comparison of a simulation study

It is difficult to treat patients with an inoperable sarcoma adjacent to the gastrointestinal (GI) tract using carbon ion radiotherapy (C-ion RT), owing to the possible development of serious GI toxicities. In such cases, spacer placement may be useful in physically separating the tumor and the GI tract. We aimed to evaluate the usefulness of spacer placement by conducting a simulation study of dosimetric comparison in a patient with sacral chordoma adjacent to the rectum treated with C-ion RT. The sacral chordoma was located in the third to fourth sacral spinal segments, in extensive contact with and compressing the rectum. Conventional C-ion RT was not indicated because the rectal dose would exceed the tolerance dose. Because we chose spacer placement surgery to physically separate the tumor and the rectum before C-ion RT, bioabsorbable spacer sheets were inserted by open surgery. After spacer placement, 67.2 Gy [relative biological effectiveness (RBE)] of C-ion RT was administered. The thickness of the spacer was stable at 13-14 mm during C-ion RT. Comparing the dose-volume histogram (DVH) parameters, Dmax for the rectum was reduced from 67 Gy (RBE) in the no spacer plan (simulation plan) to 45 Gy (RBE) in the spacer placement plan (actual plan) when a prescribed dose was administered to the tumor. Spacer placement was advantageous for irradiating the tumor and the rectum, demonstrated using the DVH parameter analysis.

An Insight into the Roles of MicroRNAs and Exosomes in Sarcoma

Sarcomas are rare solid tumors, but at least one-third of patients with sarcoma die from tumor-related disease. MicroRNA (miRNA) is a noncoding RNA that regulates gene expression in all cells and plays a key role in the progression of cancers. Recently, it was identified that miRNAs are transferred between cells by enclosure in extracellular vesicles, especially exosomes. The exosome is a 100 nm-sized membraned vesicle that is secreted by many kinds of cells and contains miRNA, mRNA, DNA, and proteins. Cancer uses exosomes to influence not only the tumor microenvironment but also the distant organ to create a premetastatic niche. The progression of sarcoma is also regulated by miRNAs and exosomes. These miRNAs and exosomes can be targeted as biomarkers and treatments. In this review, we summarize the studies of miRNA and exosomes in sarcoma.

Drug library screen reveals benzimidazole derivatives as selective cytotoxic agents for KRAS-mutant lung cancer

KRAS is one of the most frequently mutated oncogenes in human non-small cell lung cancer (NSCLC). Mutations in KRAS are detected in 30% of NSCLC cases, with most of them occurring in codons 12 and 13 and less commonly in others. Despite intense efforts to develop drugs targeting mutant KRAS, no effective therapeutic strategies have been successfully tested in clinical trials. Here, we investigated molecular targets for KRAS-activated lung cancer cells using a drug library. A total of 1271 small molecules were screened in KRAS-mutant and wild-type lung cancer cell lines. The screening identified the cytotoxic effects of benzimidazole derivatives on KRAS-mutant lung cancer cells. Treatments with two benzimidazole derivatives, methiazole and fenbendazole-both of which are structurally specific-yielded significant suppression of the RAS-related signaling pathways in KRAS-mutated cells. Moreover, combinatorial therapy with methiazole and trametinib, a MEK inhibitor, induced synergistic effects in KRAS-mutant lung cancer cells. Our study demonstrates that these benzimidazole derivatives play an important role in suppressing KRAS-mutant lung cancer cells, thus offering a novel combinatorial therapeutic approach against such cancer cells.

Development of miRNA-based therapeutic approaches for cancer patients

Over the past few decades, siRNA and miRNA have attracted a great deal of attention from researchers and clinicians. These molecules have been extensively studied from the standpoint of developing biopharmaceuticals against various diseases, including heart disease, diabetes and cancers. siRNA suppresses only a single target, whereas each miRNA regulates the expression of multiple target genes. More importantly, because miRNA are also secreted from cancer cells, and their aberrant expression is associated with tumor development and progression, they represent not only therapeutic targets but also promising biomarkers for diagnosis and prognosis. Therefore, miRNA may be more effective tools against cancers, in which multiple signal pathways are dysregulated. In this review, we summarize recent progress in the development of miRNA therapeutics for the treatment of cancer patients, and describe delivery systems for oligonucleotide therapeutics.

[MicroRNA in Body Fluids - Development of the Novel Plat Form for Cancer Therapeutics and Diagnosis]

MicroRNAs(miRNAs)are small non-coding RNAs that function in diverse biological processes and are approximately 20-22 nucleotide RNAs that regulate the expression of target genes, mainly at the post-transcriptional level. A number of studies report that miRNAs are involved in homeostatic maintenance such as cell cycle regulation, cell division and apoptosis, and that aberrant expression of miRNAs is often detected in various types of diseases, including cancer. In cancer biology, miRNAs play functional roles in tumor seeding, drug sensitivity, and metastasis. MiRNAs are also secreted through the small vesicles called exosomes, which are endosome-derived vesicles from various cell types including immune and tumor cells. In addition to cellular miRNAs, secreted miRNAs also play important roles in cancer development and metastasis. Therefore, secreted miRNAs in body fluids have been investigated as a promising biomarkers and therapeutic targets for the treatment of cancer patients. In this review, we introduce the current knowledge of miRNA functions in cancer development and discuss the clinical applications of se-miRNAs, eg, as diagnostic markers and therapeutic targets.

Drug Resistance Driven by Cancer Stem Cells and Their Niche

Drug resistance represents one of the greatest challenges in cancer treatment. Cancer stem cells (CSCs), a subset of cells within the tumor with the potential for self-renewal, differentiation and tumorigenicity, are thought to be the major cause of cancer therapy failure due to their considerable chemo- and radioresistance, resulting in tumor recurrence and eventually metastasis. CSCs are situated in a specialized microenvironment termed the niche, mainly composed of fibroblasts and endothelial, mesenchymal and immune cells, which also play pivotal roles in drug resistance. These neighboring cells promote the molecular signaling pathways required for CSC maintenance and survival and also trigger endogenous drug resistance in CSCs. In addition, tumor niche components such as the extracellular matrix also physically shelter CSCs from therapeutic agents. Interestingly, CSCs contribute directly to the niche in a bilateral feedback loop manner. Here, we review the recent advances in the study of CSCs, the niche and especially their collective contribution to resistance, since increasingly studies suggest that this interaction should be considered as a target for therapeutic strategies.

Bone turnover markers and the factors associated with atypical femur fractures among Japanese patients

Many previous reports have indicated that atypical femur fractures (AFFs) are associated with the administration of bisphosphonates (BPs). A number of risk factors and hypotheses regarding the pathogenesis of AFFs have been reported to date. The purpose of the present study was to identify the factors associated with AFFs in Japanese individuals and to elucidate the association between bone metabolism and AFFs by evaluating bone turnover markers (BTMs). We prospectively reviewed all patients with femur fractures and identified the patients with AFFs and typical femur fractures (TFFs). We collected the demographic and clinical data that were relevant to the present study, namely age, gender, affected side, affected site, concomitant medical history, and comorbid conditions, and measured the levels of BTMs within 24h after trauma. Welch's test and Fisher's exact probability test were used for the statistical analyses. A total of 338 patients, including 10 patients with AFFs and 328 patients with TFFs, were analyzed under the inclusion criteria. The use of BPs (p<0.001) and collagen disease and chronic granulomatous disease (CD/CGD) (p=0.025) were more frequently observed in patients with AFFs than in patients with TFFs, while the levels of BTMs, including N-terminal propeptides of type 1 procollagen (P1NP), isoform 5b of tartrate-resistant acid phosphatase (TRACP-5b) and undercarboxylated osteocalcin (ucOC) were significantly lower in patients with AFFs than in patients with TFFs. Furthermore, the level of TRACP-5b was found to be significantly lower in patients with atypical subtrochanteric fractures than in atypical diaphyseal fractures (p=0.025). Moreover, the levels of P1NP (p=0.016) and TRACP-5b (p=0.015) were found to be significantly lower in patients with AFFs than in patients with TFFs in a subgroup analysis of BPs users. The use of BPs was considered to be a factor associated with AFFs. Our comparison of the BTMs in patients with AFFs and TFFs indicated that the severe suppression of bone turnover was associated with the pathogenesis of AFFs. The extent of the influence of suppressed turnover on the pathogenesis of AFFs may differ depending on the fracture site.

Transplantation of cryopreserved adult human Schwann cells enhances axonal conduction in demyelinated spinal cord

Schwann cells derived from human sural nerve may provide a valuable source of tissue for a cell-based therapy in multiple sclerosis. However, it is essential to show that transplanted human Schwann cells can remyelinate axons in adult CNS and improve axonal conduction. Sections of sural nerve were removed from amputated legs of patients with vascular disease or diabetes, and Schwann cells were isolated and cryopreserved. Suspensions of reconstituted cells were transplanted into the X-irradiation/ethidium bromide lesioned dorsal columns of immunosuppressed Wistar rat. After 3-5 weeks of extensive remyelination, a typical Schwann cell pattern was observed in the lesion zone. Many cells in the lesion were immunopositive for an anti-human nuclei monoclonal antibody. The dorsal columns were removed and maintained in an in vitro recording chamber; the conduction properties were studied using field potential and intra-axonal recording techniques. The transplanted dorsal columns displayed improved conduction velocity and frequency-response properties, and action potentials conducted over a greater distance into the lesion, suggesting that conduction block was overcome. These data support the conclusion that transplantation of human Schwann cells results in functional remyelination of a dorsal column lesion.

[Characteristic improvement of the function following Schwann cell transplantation for demyelinated spinal cord]

Transplantation of Schwann cells (SCs) induced remyelination of demyelinated rat dorsal column (DC) axons and improved conduction. To investigate the difference between oligodendrocyte (OL) and SC myelination in conductive functions of axons, we compared normal DCs, demyelinated DCs, demyelinated DCs remyelinated by SC transplantation, and normal dorsal roots. All of the axons was originated from dorsal root ganglion neurons. Dorsal roots of adult rats were demyelinated at T11 by X-ray irradiation and ethidium bromide, and transplanted with SCs (3 x 10(4)) of adult rats. Three weeks later, the spinal cord was removed and pinned in a recording chamber and compound action potentials (CAPs) were recorded, to investigate conduction properties (conduction velocity and response after high frequency stimulation). Normal DCs or dorsal roots were recorded in same manner. Following transplantation of SCs, histological examination revealed SC-like patterns of remyelination in demyelinated DCs. SC transplantation improved significantly conduction properties compared to demyelinated axons, but less than normal DC. Moreover, remyelinated axons by SC transplantation showed as low amplitude of CAP as dorsal roots, but lower conduction velocity than dorsal roots. Though anatomical difference and/or time after transplantation influenced the conduction, these result suggested that SC myelination resulted in lower amplitude of CAP than OL, and SC remyelination might be insufficient for conduction velocity.

Synaptic reorganization in the substantia gelatinosa after peripheral nerve neuroma formation: aberrant innervation of lamina II neurons by Abeta afferents

Intracellular recording and extracellular field potential (FP) recordings were obtained from spinal cord dorsal horn neurons (laminae I-IV) in a rat transverse slice preparation with attached dorsal roots. To study changes in synaptic inputs after neuroma formation, the sciatic nerve was sectioned and ligated 3 weeks before in vitro electrophysiological analysis. Horseradish peroxidase labeling of dorsal root axons indicated that Abeta fibers sprouted into laminae I-II from deeper laminae after sciatic nerve section. FP recordings from dorsal horns of normal spinal cord slices revealed long-latency synaptic responses in lamina II and short-latency responses in lamina III. The latencies of synaptic FPs recorded in lamina II of the dorsal horn after sciatic nerve section were reduced. The majority of monosynaptic EPSPs recorded with intracellular microelectrodes from lamina II neurons in control slices were elicited by high-threshold nerve stimulation, whereas the majority of monosynaptic EPSPs recorded in lamina III were elicited by low-threshold nerve stimulation. After sciatic nerve section, 31 of 57 (54%) EPSPs recorded in lamina II were elicited by low-threshold stimulation. The majority of low-threshold EPSPs in lamina II neurons after axotomy displayed properties similar to low-threshold EPSPs in lamina III of control slices. These results indicate that reoccupation of lamina II synapses by sprouting Abeta fibers normally terminating in lamina III occurs after sciatic nerve neuroma formation. Furthermore, these observations indicate that the lamina II neurons receive inappropriate sensory information from low-threshold mechanoreceptor after sciatic nerve neuroma formation.

Intraparenchymal meningioma in an infant--case report

A 1-year and 10-month-old girl presented with an intraparenchymal meningioma in the left frontal lobe manifesting as grand-mal seizures. Computed tomography and magnetic resonance images revealed a round, well-demarcated mass in the left frontal lobe which was homogeneously enhanced. Angiography showed the feeding arteries of the tumor from the middle cerebral artery. The preoperative diagnosis was an intraaxial tumor. At operation, the lesion was totally embedded in the frontal lobe without any connection to the overlying dura or the ventricular system. Some small feeders from the middle cerebral artery were coagulated and the tumor was totally removed. The histological diagnosis was fibroblastic meningioma. Her postoperative course was uneventful. She was doing well 2 years after surgery. Intraparenchymal meningiomas may be seen more frequently than expected in children. Absence of dural attachment is characteristic of pediatric meningiomas.

Afferent projections to the Bötzinger complex from the upper cervical cord and other respiratory related structures in the brainstem in cats: retrograde WGA-HRP tracing

Following injection of WGA-HRP (30-60 nl, 5%) into the Bötzinger complex (Böt.c), a group of expiratory neurons in the vicinity of the retrofacial nucleus, a number of labeled neurons were observed, predominantly ipsilaterally, in the intermediate zone of the upper cervical cord at the C1 and C2 segments, the retrotrapezoid nucleus (RTN) in the ventrolateral medulla and the parabrachial-Kölliker-Fuse nuclear complex in the rostral pons. In addition, clusters of labeled cells were also observed in and around the solitary tract nucleus, nuclei ambiguus and retroambiguus, and nucleus raphe magnus. Control injections into the magnocellular tegmental field adjacent to the Böt.c resulted in a diffuse distribution of labeled neurons in the reticular formation. These results demonstrate that the Böt.c receives convergent monosynaptic axonal projections from the upper cervical spinal cord, the pontine pneumotaxic area, the RTN and several other respiratory related structures in the medulla.

Magnetic resonance imaging characteristics of choroid plexus papilloma in the fourth ventricle

The computed tomography (CT) and magnetic resonance (MR) imaging characteristics of two cases of small choroid plexus papilloma within the fourth ventricle are reported. CT showed the tumors as high density areas with postcontrast enhancement. MR imaging showed the tumors as basically isointense areas with marked enhancement by gadolinium-diethylenetriaminepenta-acetic acid. Important MR imaging findings included clear evidence of tumor attachment to the normal choroid plexus, location in the lower part of the fourth ventricle, and separation from the fourth ventricular floor.