Type and quality of sample preparation have significant impact on imaging mass spectrometry results. Though imaging of fresh-frozen tissues is considered to give the best results, they are incompatible with clinical practice, since routine diagnostics is most frequently performed using formalin-fixed tissues, and formalin-fixed paraffin-embedded material is a gold standard in histopathology. We aimed to assess utility of formalin-fixed tissue specimen processed without paraffin embedding (i.e., deep-frozen and cryo-sectioned) for MALDI imaging of both peptides and lipids. Peptide and lipid imaging was performed in fresh-frozen, FFPE and formalin-fixed/frozen samples of a mouse kidney, then composition of the resulting spectra was compared. We demonstrated similarity of spectra registered during peptide imaging in FFPE and formalin-fixed/frozen tissues, and similarity of spectra registered during lipid imaging in fresh-frozen and formalin-fixed/frozen material. Furthermore, molecular images of formalin-fixed/frozen tissue resembled the features of both fresh-frozen and FFPE tissue in the case of peptide imaging, and the features of fresh-frozen tissue in the case of lipid imaging. We conclude that tissue preserved by formalin fixation and processed without paraffin embedding can be considered as an alternative to both fresh-frozen and FFPE material.

Wedge resection was associated with significantly lower 3-year and 5-year survival rates compared to the other methods of resection. There was no significant difference in 3-year or 5-year survival rates between lobectomy and segmentectomy. Segmentectomy, but not wedge resection, could be considered an alternative to lobectomy in the treatment of patients with Stage I NSCLC.

Molecular profiling of small extracellular vesicles (sEV) isolated from plasma of cancer patients emerges as promising strategy for biomarkers discovery. We investigated the proteomic profiles of sEV immunoselected using anti‐CSPG4 antibodies from 15 melanoma patients’ plasma. The proteomes of sEV separated into melanoma cell‐derived (MTEX) and non‐malignant cell‐derived (NMTEX) were compared using high‐resolution mass spectrometry. Paired analysis identified the MTEX‐associated profile of 16 proteins that discriminated MTEX from NMETEX. We also identified the MTEX profile that discriminated between seven patients with no evidence of melanoma (NED) after therapy and eight with progressive disease (PD). Among 75 MTEX proteins overexpressed in PD patients, PDCD6IP (ALIX) had the highest discriminating value, while CNTN1 (contactin‐1) was upregulated only in MTEX of NED patients. This is the first report documenting that proteomes of tumour‐derived sEV in patients’ plasma discriminate cancer from non‐cancer and identify proteins with potential to serve as prognostic biomarkers in melanoma.

The role of adjuvant chemotherapy in stage T2-T3N0 colon cancer (CC) is controversial and there are currently no reliable factors allowing for individual selection of patients with high risk of relapse for such therapy. We searched for microRNA-based signature with prognostic significance in this group. We assessed by qRT-PCR expression of 754 microRNAs (miRNAs) in tumour samples from 85 stage pT2-3N0 CC patients treated with surgery alone. MiRNA expression was compared between two groups of patients: 40 and 45 patients who did and did not develop distant metastases after resection, respectively. Additionally, miRNA expression was compared between CC and normal colon mucosa samples and between the mismatch repair (MMR) competent and deficient tumours. Low expression of miR-1300 and miR-939 was significantly correlated with shorter distant metastasis-free survival (DMFS) in Cox univariate analysis (p.adjusted = 0.049). The expression signature of five miRNAs (miR-1296, miR-135b, miR-539, miR-572 and miR-185) was found to be prognostic [p = 1.28E−07, HR 8.4 (95 % CI: 3.81–18.52)] for DMFS and cross-validated in a leave-one-out analysis, with the sensitivity and specificity of 74 and 78 %, respectively. The expression of miR-592 was significantly associated with the MMR status (p.adjusted <0.01). The expression of several novel miRNAs were found to be tumour specific, e.g. miR-888, miR-523, miR-18b, miR-302a, miR-423-5p, miR-582-3p (p < 0.05). We developed a miRNA expression signature that may be predictive for the risk of distant relapse in early stage CC and confirmed previously reported association between miR-592 expression and MMR status.Electronic supplementary materialThe online version of this article (doi:10.1007/s10585-016-9810-1) contains supplementary material, which is available to authorized users.

BackgroundElevated temperatures induce activation of the heat shock transcription factor 1 (HSF1) which in somatic cells leads to heat shock proteins synthesis and cytoprotection. However, in the male germ cells (spermatocytes) caspase-3 dependent apoptosis is induced upon HSF1 activation and spermatogenic cells are actively eliminated.ResultsTo elucidate a mechanism of such diverse HSF1 activity we carried out genome-wide transcriptional analysis in control and heat-shocked cells, either spermatocytes or hepatocytes. Additionally, to identify direct molecular targets of active HSF1 we used chromatin immunoprecipitation assay (ChIP) combined with promoter microarrays (ChIP on chip). Genes that are differently regulated after HSF1 binding during hyperthermia in both types of cells have been identified. Despite HSF1 binding to promoter sequences in both types of cells, strong up-regulation of Hsps and other genes typically activated by the heat shock was observed only in hepatocytes. In spermatocytes HSF1 binding correlates with transcriptional repression on a large scale. HSF1-bound and negatively regulated genes encode mainly for proteins required for cell division, involved in RNA processing and piRNA biogenesis.ConclusionsObserved suppression of the transcription could lead to genomic instability caused by meiotic recombination disturbances, which in turn might induce apoptosis of spermatogenic cells. We propose that HSF1-dependent induction of cell death is caused by the simultaneous repression of many genes required for spermatogenesis, which guarantees the elimination of cells damaged during heat shock. Such activity of HSF1 prevents transmission of damaged genetic material to the next generation.