In Vivo and In Vitro Pro-Fibrotic Response of Lung-Resident Mesenchymal Stem Cells from Patients with Idiopathic Pulmonary Fibrosis

Lung-resident mesenchymal stem cells (LR-MSC) are thought to participate in idiopathic pulmonary fibrosis (IPF) by differentiating into myofibroblasts. On the other hand, LR-MSC in IPF patients present senescence-related features. It is unclear how they respond to a profibrotic environment. Here, we investigated the profibrotic response of LR-MSC isolated from IPF and control (CON) patients. LR-MSC were inoculated in mice 48 h after bleomycin (BLM) instillation to analyze their contribution to lung damage. In vitro, LR-MSC were exposed to TGFβ. Mice inoculated with IPF LR-MSC exhibited worse maintenance of their body weight. The instillation of either IPF or CON LR-MSC sustained BLM-induced histological lung damage, bronchoalveolar lavage fluid cell count, and the expression of the myofibroblast marker, extracellular matrix (ECM) proteins, and proinflammatory cytokines in the lungs. In vitro, IPF LR-MSC displayed higher basal protein levels of aSMA and fibronectin than CON LR-MSC. However, the TGFβ response in the expression of TGFβ, aSMA, and ECM genes was attenuated in IPF LR-MSC. In conclusion, IPF LR-MSC have acquired myofibroblastic features, but their capacity to further respond to profibrotic stimuli seems to be attenuated. In an advanced stage of the disease, LR-MSC may participate in disease progression owing to their limited ability to repair epithelial damage.

Detection of the EGFR G719S Mutation in Non-small Cell Lung Cancer Using Droplet Digital PCR

Objectives: The main objectives of the study were (1) to set-up a droplet digital PCR (ddPCR) assay for the non-invasive detection of G719S EGFR mutation in NSCLC patients; (2) to determine the limits of detection of the ddPCR assay for G719S mutation and (3) to compare COBAS® and ddPCR System for G719S quantification in plasma.

Materials and Methods: Blood samples were collected from 22 patients diagnosed with advanced NSCLC. Then, plasma ctDNA was extracted with the Qiagen Circulating Nucleic Acids kit and quantified by QuantiFluor® dsDNA System. The mutational study of EGFR was carried out by digital droplet PCR (ddPCR) with the QX200 Droplet Digital PCR System with specific probes and primers.

Results: We observed the lowest percentage of G719S mutant allele could be detected in a wildtype background was 0.058%. In the specificity analysis, low levels of G719S mutation were detected in healthy volunteers with a peak of 21.65 mutant copies per milliliter of plasma and 6.35 MAFs. In those patients whose tissue biopsy was positive for G719S mutation, mutant alleles could also be detected in plasma using both ddPCR and COBAS® System. Finally, when mutational status was studied using both genotyping techniques, higher mutant copies/ml and higher mutant allele fraction (MAF) correlated with higher Semiquantitative Index obtained by COBAS®.

Conclusions: Although tissue biopsies cannot be replaced due to the large amount of information they provide regarding tumor type and structure, liquid biopsy and ddPCR represents a new promising strategy for genetic analysis of tumors from plasma samples. In the present study, G719S mutation was detected in a highly sensitive manner, allowing its monitorization with a non-invasive technique.

Carcinosarcoma of the submandibular and sublingual salivary glands. A case report and review of the literature

Carcinosarcoma of the salivary gland is a rare lesion, estimated at 0.2% of malignant salivary gland tumors [1, 2]. The present article describes a case occurring in a 54-year-old man with a submandibular mass in the right neck. Histologically, this lesion was a carcinosarcoma which involves the submandibular and the sublingual glands. Its stromal component was a chondrosarcoma and the epithelial one was an undifferentiated carcinoma in the whole tumor, with areas of adenoid cystic carcinoma in the sublingual gland. To our knowledge, we have not found any previously reported carcinosarcoma involving the sublingual gland.

Atypical fibroxanthoma with osteoclast-like giant cells

Atypical fibroxanthoma has a wide spectrum of histological appearances. A variant recently described is atypical fibroxanthoma with osteoclast-like giant cells. One case of this rare tumour is described. The tumour arose on the forehead of an 87-year-old woman in the form of a subepidermal nodule. The lesion was incompletely excised and recurred 6 months later without showing any characteristics of aggression. Six months after the second operation the patient was well and showed no signs of tumour recurrence. Immunohistological findings showed a "fibrohistiocytic" profile and were similar to those observed in other lesions rich in osteoclast-like giant cells. Flow cytometry revealed the diploid nature of the primary and the recurrent tumour. Atypical fibroxanthoma with osteoclast-like giant cells is a new variant of atypical fibroxanthoma that must be recognized by pathologists, since it can be confused with other benign and malignant tumours with a high proportion of multinucleate osteoclast-like giant cells.