BRAF V600E-induced distinct DNA damage response defines the therapeutic potential of p53 activation for TP53 wild-type colorectal cancer.

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

[A Case of Palliative Abdominoperineal Resection and Perineal Reconstruction by Gluteus Maximus Flap following Regrowth of Primary Anal Canal Cancer with the Perianal Skin Infiltration after CRT].

An 85-year-old woman who visited the hospital with sores on the perianal skin was diagnosed with squamous cell carcinoma of the anal canal(cT3N1aM0, cStage ⅢC). She received chemoradiotherapy(radiation total 54 Gy/30 Fr, mitomycin C/capecitabine). The tumor initially shrank, but regrowth of the primary lesion, extensive perianal skin infiltration, and the appearance of para aortic lymph node metastases was observed 6 months later. Laparoscopic abdominoperineal resection was performed to mitigate strong local symptoms. The perineal defect was repaired with bilateral gluteus maximus flap(V- Y flap). The operation prevented anal pain and improved ADL. The patient is currently undergoing chemotherapy 7 months after surgery. We report the case with a review of the literature in which ADL was improved by salvage surgery for tumor regrowth with severe local symptoms and distant metastases after chemoradiotherapy for squamous cell carcinoma of the anal canal.

A case of an epithelioid glioblastoma with the BRAF V600E mutation colocalized with BRAF intact low-grade diffuse astrocytoma.

Epithelioid glioblastomas are one of the rarest histological variants of glioblastomas, which are not formally recognized by the World Health Organization (WHO) classification. Epithelioid glioblastomas usually occur as primary lesions, but there have been several reports of secondary epithelioid glioblastomas or epithelioid glioblastomas with pre- or co-existing lesions to date. The serine/threonine-protein kinase B-Raf (BRAF) V600E mutation has been found at a high frequency of 54% in epithelioid glioblastomas. We present a case of a 26-year-old female patient with an epithelioid glioblastoma with the BRAF V600E mutation in her right frontal lobe. In the present case, a low-grade diffuse astrocytoma component had colocalized with the epithelioid glioblastoma. The component presented prominent calcification on neuroimages as well as by histology, and low-grade diffuse astrocytoma was considered to be a precursor lesion of an epithelioid glioblastoma. However, the BRAF V600E mutation was detected only in epithelioid glioblastoma but not in low-grade diffuse astrocytoma. To the best of our knowledge, this is the first report demonstrating a discrepancy in the BRAF V600E mutation states between epithelioid glioblastoma and colocalized low-grade astrocytoma.

Prolonged Gut Dysbiosis and Fecal Excretion of Hepatitis A Virus in Patients Infected with Human Immunodeficiency Virus.

Hepatitis A virus (HAV) causes transient acute infection, and little is known of viral shedding via the duodenum and into the intestinal environment, including the gut microbiome, from the period of infection until after the recovery of symptoms. Therefore, in this study, we aimed to comprehensively observe the amount of virus excreted into the intestinal tract, the changes in the intestinal microbiome, and the level of inflammation during the healing process. We used blood and stool specimens from patients with human immunodeficiency virus who were infected with HAV during the HAV outbreak in Japan in 2018. Moreover, we observed changes in fecal HAV RNA and quantified the plasma cytokine level and gut microbiome by 16S rRNA analysis from clinical onset to at least 6 months after healing. HAV was detected from clinical onset up to a period of more than 150 days. Immediately after infection, many pro-inflammatory cytokines were elicited, and some cytokines showed different behaviors. The intestinal microbiome changed significantly after infection (dysbiosis), and the dysbiosis continued for a long time after healing. These observations suggest that the immunocompromised state is associated with prolonged viral shedding into the intestinal tract and delayed recovery of the intestinal environment.

Hybrid approach with laparoscopic wall-inversion surgery and single-incision intragastric surgery for intraluminal gastrointestinal stromal tumor: A case report.

Laparoscopic wedge resection (LWR) for intraluminal gastrointestinal stromal tumor (GIST) leads to excessive resection of normal gastric wall. We report a case of GIST around the cardia successfully treated with full-thickness partial resection using a hybrid approach of laparoscopic surgery and single-incision intragastric surgery (SIIGS). A 69-year-old woman had a 5 cm intraluminal GIST at the posterior wall around the cardia. Submucosal injection of glycerin and indigo carmine was performed with transoral endoscopy. Circumferential seromuscular incision followed by placement of seromuscular sutures to invert the lesion into the stomach was performed under laparoscopy. By SIIGS, resection of the inverted mucosa and retrieval of the tumor were completed. A hybrid approach consisting of laparoscopic wall-inversion surgery and SIIGS was useful for intraluminal GIST and may expand the indications for laparoscopic wall-inversion surgery by removing size limitations.

A Rare Case of Thyrotropin-Secreting Pituitary Adenoma Coexisting with Papillary Thyroid Carcinoma Presenting with Visual Disturbance without Hyperthyroidism.

BACKGROUND: Thyroid-stimulating hormone-secreting pituitary adenomas (TSHomas) are uncommon, and majority of the patients present with symptoms of hyperthyroidism. Herein, we report the first case of TSHoma with differentiated thyroid carcinoma (DTC) that presented with visual disturbance without any clinical feature of hyperthyroidism. CASE DESCRIPTION: A 57-year-old man presented with left temporal hemianopsia of his left eye without any sign of hyperthyroidism. A mass lesion in the sellar and suprasellar region compressing the optic nerves was identified via magnetic resonance imaging. Free thyroxine and free triiodothyronine levels were slightly elevated, whereas the serum level of thyroid-stimulating hormone remained within normal range. Further endocrinologic examination led to the preoperative diagnosis of TSHoma. Ultrasonography and 111In-octreotide scan showed a mass lesion in left lobe of the thyroid gland, and subsequent thyroid aspiration biopsy confirmed the diagnosis of papillary thyroid carcinoma. After administration of short-acting octreotide to prevent thyrotoxic crisis in the perioperative period, the tumor was removed via endoscopic transnasal-transsphenoidal surgery, and the pathologic diagnosis of TSHoma was made. His visual acuity improved, and free triiodothyronine and free thyroxine levels normalized. He underwent thyroidectomy 3 months later after endoscopic transnasal-transsphenoidal surgery. CONCLUSIONS: Herein, we report the first case of TSHoma with DTC that presented with visual disturbance without any clinical feature of hyperthyroidism and reviewed the 13 reported cases of TSHoma coexisting with DTC. The optimal treatment strategy in patients with TSHoma and coexistent DTC has not been established, and individualized therapeutic strategies are needed.

A novel single virus infection system reveals that influenza virus preferentially infects cells in g1 phase.

BACKGROUND: Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA), a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized. METHODS/RESULTS: To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm) at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1) the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins) than the membranes of cells in S/G2/M-phase; 2) the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3) S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition. CONCLUSIONS: A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

Thymoma hyalinized by steroid therapy in myasthenia gravis.

We encountered a 72-year-old woman with myasthenia gravis and thymoma who received glucocorticoid therapy for respiratory failure before undergoing thymectomy. After the antiacetylcholine receptor antibody titer was normalized, and the thymoma shrunk with prednisolone, the patient was free from symptoms. On pathological examination, the majority of the thymoma (type B2) had been hyalinized. Preoperative steroid therapy was effective in stabilizing myasthenia gravis and in inducing apoptosis of both epithelial and lymphocytic components of the thymoma.