CRISPR Loss-of-Function Screen Identifies the Hippo Signaling Pathway as the Mediator of Regorafenib Efficacy in Hepatocellular Carcinoma.

Regorafenib is used for hepatocellular carcinoma (HCC), but its response does not last long, partly due to chemoresistance acquisition. We performed a clustered regularly interspaced short palindromic repeats (CRISPR)-based loss-of-function genetic screen and aimed to discover molecules involved in regorafenib resistance in HCC. Xenograft tumors established from Cas9-expressing HCC cells with pooled CRISPR kinome libraries were treated with regorafenib or a vehicle. Sequencing analysis identified 31 genes, with the abundance of multiple guide RNAs increased in regorafenib-treated tumors compared to that in vehicle-treated tumors, including 2 paralogues, LATS2 and LATS1, core components of the Hippo signaling pathway. Notably, all eight designed guide RNAs targeting LATS2 increased in regorafenib-treated tumors, suggesting that LATS2 deletion confers regorafenib resistance in HCC cells. LATS2 knockdown significantly mitigated the cytotoxic and proapoptotic effects of regorafenib on HCC cells. LATS2 inhibition stabilized the Hippo signaling mediator YAP, leading to the upregulation of antiapoptotic Bcl-xL and the multidrug resistance transporter ABCB1. Among 12 hepatoma cell lines, the half maximal inhibitory concentration (IC50) values of regorafenib were positively correlated with any of YAP, Bcl-xL and ABCB1 levels. The inhibition of YAP or Bcl-xL in regorafenib-insensitive HCC cells restored their susceptibility to regorafenib. In conclusion, our screen identified the Hippo signaling pathway as the mediator of regorafenib efficacy in HCC.

[A case of pancreatic pseudocyst associated with pancreatic cancer successfully treated with endoscopic pseudocyst drainage, which allowed continuation of chemotherapy].

We report a case of pancreatic pseudocyst associated with pancreatic cancer that was successfully treated with endoscopic pseudocyst drainage, which allowed continuation of chemotherapy. A 74-year-old woman complaining of jaundice was diagnosed with locally advanced cancer in the head of the pancreas, and she underwent chemotherapy with gemcitabine. One month later, she was admitted to our hospital for severe epigastralgia, and she diagnosed with a pancreatic pseudocyst that was 14 cm in diameter. Endoscopic ultrasonography-guided pseudocyst drainage was successfully performed. The amylase concentration of pseudocyst fluid was 13,320 U/L, and bacterial culture was negative. The epigastralgia soon resolved, but 1 week later, the size of the pseudocyst was 12 cm in diameter. Endoscopic retrograde pancreatography revealed communication of the pancreatic duct with the pseudocyst. A pancreatic stent was placed. The patient again underwent chemotherapy for 3 months, without major complications. The pseudocyst was no longer visible 3 months after stent placement. The patient died of pancreatic cancer with peritonitis carcinomatosa, 6 months after the initial diagnosis.

A case of spontaneous splenic rupture during chemotherapy for B-cell chronic lymphoid leukemia.

Spontaneous splenic rupture is a life-threatening disease and an important differential diagnosis of acute abdomen. Early clinical diagnosis and rapid intervention is required to ensure patient survival. Spontaneous splenic rupture may be induced by hematological, inflammatory or infiltrative diseases affecting the spleen. Splenomegaly may also significantly increase the risk of rupture. Other contributory factors include male, adulthood, rapid growth of the spleen and splenic abscess. Here, we present the case of a 69-year-old man who was undergoing chemotherapy for B-cell chronic lymphoid leukemia. He was admitted to our hospital after he suddenly developed persistent upper abdominal pain. Computed tomography and ultrasonography revealed accumulation of free fluid in and around the spleen. He was diagnosed as having spontaneous splenic rupture and an emergency operation was performed. During the operation, we found a massively enlarged spleen with several capsular tears, and performed a splenectomy. The patient made a good recovery. Pathological examination revealed that the spleen was infiltrated by CD20-, CD5- and CD23-positive lymphoid blasts. We encountered a case of spontaneous splenic rupture in a patient receiving chemotherapy for exacerbating B-cell chronic lymphoid leukemia. In a case of abdominal pain of acute onset in patients with hematological disease, spontaneous splenic rupture should be suspected.

[Synchronous double cancer of the gallbladder and rectum successfully treated with S-1 as second-line chemotherapy- a case report].

A 66-year-old man was referred to our hospital with obstructive jaundice. Computed tomography(CT)scan showed thickening of the gallbladder wall, invasion into the liver bed, and thickening of the rectal wall. Colonoscopy revealed a type 2 rectal cancer, in which adenocarcinoma was identified by endoscopic biopsy. He was diagnosed with double-cancer of the gallbladder and rectum. Because his gallbladder cancer was more life threatening than his rectal cancer, gemcitabine was administered at 1, 000 mg/m2 on days 1, 8, and 15 of a 28-day course. After 3 courses of gemcitabine, the CT scan showed that the lymph nodes in the hepatoduodenal ligament had been enlarged, and duodenal stenosis had occurred as a result of gallbladder cancer invasion. S-1 was administered orally at doses of 120 mg/day twice daily on days 1-28 of a 42-day course. Partial response was confirmed by CT scan. After 8 courses of S-1, the gallbladder cancer had progressed and liver metastases had appeared. He subsequently died of disease progression. He survived for 17 months after the first course of chemotherapy, and the progression-free survival with S-1 was 10 months. Therefore, S-1 could be an effective agent for synchronous double cancer of the gallbladder and rectum.

[Case of primary hepatic neuroendocrine carcinoma diagnosed by needle biopsy].

The patient was a 55-year-old man with a large hepatic tumor measuring 12 × 12 cm in the left lobe. To obtain the histological diagnosis, the target liver biopsy was performed. Histologically, the tumor revealed as a neuroendocrine carcinoma. After the diagnosis, he received the chemotherapy (CTX) with etoposide and cisplatin. Serum levels of NSE and the tumor size were decreased after the first course of CTX. We here report a case of primary hepatic neuroendocrine carcinoma treated with CTX following the diagnosis by the needle biopsy.

Poorly differentiated endocrine carcinoma of the pancreas responded to gemcitabine: Case report.

Poorly differentiated endocrine carcinoma (PDEC) of the pancreas is a rare and aggressive tumor. First-line treatment is commonly a combination of etoposide and cisplatin, but there is no consensus regarding further treatment recommendations. In this report, we describe a case of pancreatic PDEC treated with gemcitabine as third-line chemotherapy. A 62-year-old man with pancreatic PDEC was administered etoposide plus cisplatin as first-line treatment; he then received irinotecan for tumor relapse. However, because irinotecan induced ileus in this patient, we chose gemcitabine as third-line chemotherapy. After two cycles of gemcitabine (1000 mg/m(2) on days 1, 8 and 15 every 4 wk), a partial tumor response was noted by computed tomography (approximately 68% reduction in tumor size). Our patient survived for 15 mo after diagnosis. This is a rare case of unresectable pancreatic PDEC, which showed a partial response to gemcitabine after the failure of two other regimens. Gemcitabine could be an effective treatment option for pancreatic PDEC that is resistant to other treatments.