Microsatellite Status Detection in Gastrointestinal Cancers: PCR/NGS Is Mandatory in Negative/Patchy MMR Immunohistochemistry.

BACKGROUND: Microsatellite instability (MSI) is a predictive biomarker for immune checkpoint inhibitors. The main goal was to investigate the discordance between IHC and PCR/NGS for MSI testing in gastrointestinal cancers. METHODS: Two series were analyzed through IHC for mismatch-repair-system proteins (MMRP) and PCR, with one series of 444 colorectal cancers (CRC) and the other of 176 gastric cancers (GC). All cases with discordant results between IHC and PCR were analyzed by NGS. IHC staining was evaluated as follows: proficient MMR (pMMR), with all MMR positive; deficient MMR (dMMR), with the loss of one heterodimer; and cases with the loss/patchy expression of one MMR (lo-paMMR). Cases with instability in at least two markers by PCR were MSI-high (MSI-H) and with instability in one marker, MSI-low (MSI-L). Cases without instability were evaluated as microsatellite-stable (MSS). RESULTS: In the CRC cohort, 15 out of 444 cases were dMMR and 46 lo-paMMR. Among the 15 dMMR, 13 were MSI-H and 2 MSS. Among the 46 lo-paMMR, 13 were MSI-H and 33 were MSS. In the GC cohort, 13 out of 176 cases were dMMR and 6 cases lo-paMMR. Among the 13 dMMR, 12 were MSI-H and only 1 was MSS. All six lo-paMMR cases were MSS. All NGS results were in agreement with PCR. CONCLUSIONS: In clinical practice, MMR-IHC could be used as a screening test and additional molecular analysis is mandatory exclusively in cases carrying loss/patchy MMR-IHC.

Characterization of the Rx1-dependent transcriptome during early retinal development.

BACKGROUND: The transcription factor Rx1, also known as Rax, controls key properties of retinal precursors including migration behavior, proliferation, and maintenance of multipotency. However, Rx1 effector genes are largely unknown. RESULTS: To identify genes controlled by Rx1 in early retinal precursors, we compared the transcriptome of Xenopus embryos overexpressing Rx1 to that of embryos in which Rx1 was knocked-down. In particular, we selected 52 genes coherently regulated, i.e., actived in Rx1 gain of function and repressed in Rx1 loss of function experiments, or vice versa. RT-qPCR and in situ hybridization confirmed the trend of regulation predicted by microarray data for the selected genes. Most of the genes upregulated by Rx1 are coexpressed with this transcription factor, while downregulated genes are either not expressed or expressed at very low levels in the early developing retina. Putative direct Rx1 target genes, activated by GR-Rx1 in the absence of protein synthesis, include Ephrin B1 and Sh2d3c, an interactor of ephrinB1 receptor, which represent candidate novel effectors for the migration promoting activity of Rx1. CONCLUSIONS: This study identifies previously undescribed Rx1 regulated genes mainly involved in transcription regulation, cell migration/adhesion, and cell proliferation that contribute to delineate the molecular mechanisms underlying Rx1 activities.

Prognosis of patients with spontaneous rupture of hepatocellular carcinoma in cirrhosis.

The treatment of cirrhotic patients with spontaneous rupture of hepatocellular carcinoma (HCC) is controversial and largely dependent on general conditions of the patients and compensation of the underlying cirrhosis. We retrospectively reviewed clinical, imaging and surgical records of 24 consecutive cirrhotic patients (17 males, 7 females; age range 52-88 years) with hemoperitoneum from spontaneous rupture of HCC observed from June 2004 to January 2010 at our Institution. When indicated, patients were referred to surgery or trans-arterial embolization (TAE). Advanced decompensated patients were conservatively treated and clinically followed up. Spontaneous rupture of HCC was assessed by aspiration of bloody ascites at paracentesis in all cases. The presence of large blood-clots over HCC and liver surface at US and/or CT was considered a specific sign of ruptured HCC in 14 cases. In two out of four patients who underwent TAE active bleeding from tumor surface could be demonstrated. In 2 cases, the active hemorrhage from the HCC surface could be assessed by contrast-enhanced ultrasonography. Four out of 24 patients underwent surgery. Three out of four of these patients died within 2 weeks, 8 months, and 20 months after operation, respectively. The remaining patient is still alive at 52 months follow-up. Four patients underwent TAE and died at 1, 2, 6 and 10 months after treatment, because of recurrent peritoneal bleeding and/or liver failure. Sixteen patients with ruptured HCC in the advanced Child C cirrhosis were treated conservatively with blood derivative transfusion and with procoagulant drugs. All patients, but one died within 2-18 days. One patient survived the acute hemorrhage from ruptured HCC and died of liver failure after 3 months. We concluded that spontaneous rupture of HCC is usually a fatal event in patients with poor liver function, even after successful TAE. In compensated patients, timely surgical treatment can result in long term and even tumor-free survival of the patient.