Approximately 10% to 15% of human cancers lack detectable telomerase activity, and a subset of these maintain telomere lengths by the telomerase-independent telomere maintenance mechanism termed alternative lengthening of telomeres (ALT). The ALT phenotype, relatively common in subtypes of sarcomas and astrocytomas, has rarely been reported in epithelial malignancies. However, the prevalence of ALT has not been thoroughly assessed across all cancer types. We therefore comprehensively surveyed the ALT phenotype in a broad range of human cancers. In total, two independent sets comprising 6110 primary tumors from 94 different cancer subtypes, 541 benign neoplasms, and 264 normal tissue samples were assessed by combined telomere-specific fluorescence in situ hybridization and immunofluorescence labeling for PML protein. Overall, ALT was observed in 3.73% (228/6110) of all tumor specimens, but was not observed in benign neoplasms or normal tissues. This is the first report of ALT in carcinomas arising from the bladder, cervix, endometrium, esophagus, gallbladder, kidney, liver, and lung. Additionally, this is the first report of ALT in medulloblastomas, oligodendrogliomas, meningiomas, schwannomas, and pediatric glioblastoma multiformes. Previous studies have shown associations between ALT status and prognosis in some tumor types; thus, further studies are warranted to assess the potential prognostic significance and unique biology of ALT-positive tumors. These findings may have therapeutic consequences, because ALT-positive cancers are predicted to be resistant to anti-telomerase therapies.

The identification of biomarkers indicating the level of aggressiveness of prostate cancer (PCa) will address the urgent clinical need to minimize the general overtreatment of patients with non-aggressive PCa, who account for the majority of PCa cases. Here, we isolated formerly N-linked glycopeptides from normal prostate (n = 10) and from non-aggressive (n = 24), aggressive (n = 16), and metastatic (n = 25) PCa tumor tissues and analyzed the samples using SWATH mass spectrometry, an emerging data-independent acquisition method that generates a single file containing fragment ion spectra of all ionized species of a sample. The resulting datasets were searched using a targeted data analysis strategy in which an a priori spectral reference library representing known N-glycosites of the human proteome was used to identify groups of signals in the SWATH mass spectrometry data. On average we identified 1430 N-glycosites from each sample. Out of those, 220 glycoproteins showed significant quantitative changes associated with diverse biological processes involved in PCa aggressiveness and metastasis and indicated functional relationships. Two glycoproteins, N-acylethanolamine acid amidase and protein tyrosine kinase 7, that were significantly associated with aggressive PCa in the initial sample cohort were further validated in an independent set of patient tissues using tissue microarray analysis. The results suggest that N-acylethanolamine acid amidase and protein tyrosine kinase 7 may be used as potential tissue biomarkers to avoid overtreatment of non-aggressive PCa.

No abstract

Adenocarcinoma with enteric differentiation is a rare subtype of lung adenocarcinoma that is recognized as a variant type of primary adenocarcinoma in the 2015 World Health Organization classification of lung tumors. Published immunohistochemistry studies show variable staining pattern for CDX-2 ranging from positivity in 71% of the cases to no staining. As little is known about CDX-2 expression in lung adenocarcinomas lacking histologic features of enteric differentiation, our aim was to determine the rate of CDX-2 positivity in non-enteric-type lung adenocarcinomas. We performed immunohistochemistry for CDX-2, CK7, CK20, TTF-1, napsin A, and p40 using 4-μm sections of a previously constructed tissue microarray containing 93 primary lung adenocarcinomas that lack morphologic evidence of enteric differentiation. The cohort included 22 well, 54 moderately, and 17 poorly differentiated tumors (55 female, 38 male; age range: 42 to 86, median: 64.5). All 93 tumors were strongly CK7 positive, whereas variable CK20 staining was seen in 4 tumors (1 strong, 1 moderate, and 2 focal). Both TTF-1 and napsin A were positive in 81 of 93 (87%) tumors with only 6 of 93 (6.5%) tumors negative for both the markers. Eleven tumors were CDX-2 positive (5 strong, 3 moderate, and 3 weak), all of which were also TTF-1 and napsin A positive and p40 negative. One CDX-2-positive tumor showed focal CK20 staining. Mutation studies for EGFR/K-ras/ALK were performed in four CDX-2-positive tumors and detected a K-ras mutation in one of them. CDX-2 positivity can be seen in a subset (12%) of lung adenocarcinoma. These tumors are CK7, TTF-1, and napsin A positive and p40 negative. Focal CK20 staining is only seen in rare cases. CDX-2 positivity should not be used as the only criteria to exclude lung origin.