Does serous tubal intraepithelial carcinoma (STIC) metastasize? The clonal relationship between STIC and subsequent high-grade serous carcinoma in BRCA1/2 mutation carriers several years after risk-reducing salpingo-oophorectomy.

OBJECTIVE: The majority of high-grade serous carcinomas (HGSC) of the ovary, fallopian tube, and peritoneum arise from the precursor lesion called serous tubal intraepithelial carcinoma (STIC). It has been postulated that cells from STICs exfoliate into the peritoneal cavity and give rise to peritoneal HGSC several years later. While co-existent STICs and HGSCs have been reported to share similarities in their mutational profiles, clonal relationship between temporally distant STICs and HGSCs have been infrequently studied and the natural history of STICs remains poorly understood. METHODS: We performed focused searches in two national databases from the Netherlands and identified a series of BRCA1/2 germline pathogenic variant (GPV) carriers (n = 7) who had STIC, and no detectable invasive carcinoma, at the time of their risk-reducing salpingo-oophorectomy (RRSO), and later developed peritoneal HGSC. The clonal relationship between these STICs and HGSCs was investigated by comparing their genetic mutational profile by performing next-generation targeted sequencing. RESULTS: Identical pathogenic mutations and loss of heterozygosity of TP53 were identified in the STICs and HGSCs of five of the seven patients (71%), confirming the clonal relationship of the lesions. Median interval for developing HGSC after RRSO was 59 months (range: 24-118 months). CONCLUSION: Our results indicate that cells from STIC can shed into the peritoneal cavity and give rise to HGSC after long lag periods in BRCA1/2 GPV carriers, and argues in favor of the hypothesis that STIC lesions may metastasize.

Progression of ductal carcinoma in situ to invasive breast cancer: comparative genomic sequencing.

Several models have been described as potential mechanisms for the progression of ductal carcinoma in situ (DCIS) to invasive breast cancer (IBC). The aim of our study was to increase our understanding of DCIS progression by using massive parallel sequencing of synchronous DCIS and IBC. We included patients with synchronous DCIS and IBC (n = 4). Initially, IBC and normal tissue were subjected to whole exome sequencing. Subsequently, targeted sequencing was performed to validate those tumor-specific variants identified by whole exome sequencing. Finally, we analyzed whether those specific variants of the invasive component were also present in the DCIS component. There was a high genomic concordance between synchronous DCIS and IBC (52 out of 92 mutations were present in both components). However, the remaining mutations (40 out of 92) were restricted to the invasive component. The proportion of tumor cells with these mutations was higher in the invasive component compared to the DCIS component in a subset of patients. Our findings support the theory that the progression from DCIS to IBC could be driven by the selection of subclones with specific genetic aberrations. This knowledge improves our understanding of DCIS progression, which may lead to the identification of potential markers of progression and novel therapeutic targets in order to develop a more personalized treatment of patients with DCIS.

Germline variant in MSX1 identified in a Dutch family with clustering of Barrett's esophagus and esophageal adenocarcinoma.

The vast majority of esophageal adenocarcinoma cases are sporadic and caused by somatic mutations. However, over the last decades several families have been identified with clustering of Barrett's esophagus and esophageal adenocarcinoma. This observation suggests that one or more hereditary factors may play a role in the initiation of Barrett's esophagus and esophageal adenocarcinoma in these families. A Dutch family with clustering of Barrett's esophagus and esophageal adenocarcinoma was identified. Normal DNA obtained from the proband diagnosed with Barrett's esophagus was analyzed with SNP array and exome sequencing. A custom-made panel consisting of potential germline variants was verified in the normal DNA of the affected family members. In addition, the respective tumors were analyzed for somatic loss of the wild type allele or the presence of an inactivating somatic mutation in the wild type allele. Exome sequencing revealed 244 candidate variants in the normal DNA of the proband, of which 212 variants were verified successfully. After the normal DNA of the affected family members was analyzed for the presence of the 212 potential germline variants and subsequently the respective tumors, only one potential germline variant in MSX1 (chr4: 4861985 T > G, c.359T > G, p.V120G, NM_002448) showed loss of the wild type allele in the tumor DNAs of the affected family members. A germline variant in MSX1 was identified in a Dutch family with clustering of Barrett's esophagus and esophageal adenocarcinoma. This finding indicates that the germline defect in MSX1 may be associated with Barrett's esophagus and cancer in this particular family.

IDH1 mutations in low-grade astrocytomas predict survival but not response to temozolomide.

BACKGROUND: Mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) have been implicated in tumorigenesis of gliomas. Patients with high-grade astrocytomas with IDH1 or IDH2 mutations were reported to have a better survival, but it is unknown if this improved survival also holds for low-grade astrocytoma and whether these mutations predict outcome to specific treatment. METHODS: We retrospectively investigated the correlation of IDH1 and IDH2 mutations with overall survival and response to temozolomide in a cohort of patients with dedifferentiated low-grade astrocytomas treated with temozolomide at the time of progression after radiotherapy. RESULTS: IDH1 mutations were present in 86% of the 49 progressive astrocytomas. No mutations in IDH2 were found. Presence of IDH1 mutations were early events and significantly improved overall survival (median survival 48 vs 98 months), but did not affect outcome of temozolomide treatment. CONCLUSION: These results indicate that IDH1 mutations identify a subgroup of gliomas with an improved survival, but are unrelated to the temozolomide response.

Molecular dissection of the chromosome band 7q21 amplicon in gastroesophageal junction adenocarcinomas identifies cyclin-dependent kinase 6 at both genomic and protein expression levels.

Amplification of chromosome band 7q21 has been frequently detected in various types of cancer including gastroesophageal junction (GEJ) adenocarcinomas. At present, no gene has been disclosed that can explain this frequent amplification of 7q21 in GEJ carcinomas. Therefore, a detailed genomic analysis of the 7q21 region was performed on a selected series of GEJ adenocarcinomas, i.e., 14 primary adenocarcinomas and 10 cell lines, by array comparative genomic hybridization (aCGH) with a 7q11.22-q31.2 contig array. A distinct peak of amplification was identified at 92.1 Mb in 7q21.2, precisely comprising cyclin-dependent kinase 6 (CDK6), a gene involved in cell cycle regulation. A smaller peak was seen at 116.2 Mb in 7q31.2, the locus of the MET proto-oncogene. No distinct peak was detected for the hepatocyte growth factor (HGF) at 81.3 Mb in 7q21.11. An immunoprofile of HGF, CDK6 and MET revealed a strong correlation between aCGH and immunohistochemical protein expression for CDK6 (P = 0.002). Furthermore, immunohistochemistry did not show expression of CDK6 in Barrett's dysplasia and carcinoma in situ, correlating expression of CDK6 with a malignant phenotype. We conclude that high-resolution genomic analysis and immunoprofiling identify CDK6 as the main candidate target for the recurrent amplification of 7q21 in GEJ adenocarcinomas.

Somatostatin receptor in human hepatocellular carcinomas: biological, patient and tumor characteristics.

BACKGROUND/AIM: The evidence on the efficacy of somatostatin analogues in the treatment of hepatocellular carcinoma (HCC) in humans is conflicting. A variety of human tumors demonstrate somatostatin receptors. All subtypes bind human somatostatin with high affinity, while somatostatin analogues bind with high affinity to somatostatin receptor subtype 2 (sst2). We investigated the sst2 expression in HCC and examined whether HCCs expressing sst2 are a distinct subgroup. PATIENTS AND METHODS: Forty-five human HCCs were tested for sst2 expression and biological alterations. The proliferative capacity was determined with Ki67 immunostaining and the DNA ploidy status was measured by fluorescent in situ hybridization with a chromosome 1-specific repetitive DNA probe. Expression of tumor suppressor genes (p16, p53 and Rb1) was measured by immunohistochemistry. RESULTS: sst2 expression was detected in 30 tumors (67%). No correlation existed between sst2 expression and the immunoprofiles of the tumor suppressor genes, aneuploidy, proliferation, age, gender, alpha-fetoprotein levels, tumor size, tumor grade and underlying liver disease. CONCLUSION: In 67% of the patients with HCC, sst2 could be detected in the tumor. No clinical, pathological or biological characteristics were specific for sst2-positive tumors.

High-resolution array comparative genomic hybridization of chromosome 8q: evaluation of putative progression markers for gastroesophageal junction adenocarcinomas.

Amplification of 8q is frequently found in gastroesophageal junction (GEJ) cancer. It is usually detected in high-grade, high-stage GEJ adenocarcinomas. Moreover, it has been implicated in tumor progression in other cancer types. In this study, a detailed genomic analysis of 8q was performed on a series of GEJ adenocarcinomas, including 22 primary adenocarcinomas, 13 cell lines and two xenografts, by array comparative genomic hybridization (aCGH) with a whole chromosome 8q contig array. Of the 37 specimens, 21 originated from the esophagus and 16 were derived from the gastric cardia. Commonly overrepresented regions were identified at distal 8q, i.e. 124-125 Mb (8q24.13), at 127-128 Mb (8q24.21), and at 141-142 Mb (8q24.3). From these regions six genes were selected with putative relevance to cancer: ANXA13, MTSS1, FAM84B (alias NSE2), MYC, C8orf17 (alias MOST-1) and PTK2 (alias FAK). In addition, the gene EXT1 was selected since it was found in a specific amplification in cell line SK-GT-5. Quantitative RT-PCR analysis of these seven genes was subsequently performed on a panel of 24 gastroesophageal samples, including 13 cell lines, two xenografts and nine normal stomach controls. Significant overexpression was found for MYC and EXT1 in GEJ adenocarcinoma cell lines and xenografts compared to normal controls. Expression of the genes MTSS1, FAM84B and C8orf17 was found to be significantly decreased in this set of cell lines and xenografts. We conclude that, firstly, there are other genes than MYC involved in the 8q amplification in GEJ cancer. Secondly, the differential expression of these genes contributes to unravel the biology of GEJ adenocarcinomas.

Long-term survival after radical resection for pancreatic head and ampullary cancer: a potential role for the EGF-R.

BACKGROUND/AIM: Pancreatic cancer has a dismal prognosis. Ampullary cancer (defined as cancer of the ampulla of Vater or the distal common bile duct) has a better prognosis and is thought to be a biologically different tumor. The aim of this study was to find factors that could predict survival after radical (R-0) resection for pancreatic head and ampullary cancers. METHODS: We analyzed clinical and pathological data from 93 patients who underwent a true R-0 resection for pancreatic head or ampullary cancer. Furthermore, we performed a tissue microarray protein expression analysis for several growth factor receptors and oncogenes: HER-2, EGF-R, ER, PR, C-myc, p53, p16, RB-1, and chromogranin A as a neuroendocrine differentiation marker. RESULTS: Median survival (14 vs. 42 months) and time to recurrence (16 vs. 42 months) were significantly longer for ampullary than for pancreatic head cancers. Preoperative pain, perineural invasion, lymph node metastasis, and tumor differentiation grade are indicators of a poor survival. No differences in protein expression were found between groups, except for EGF-R which was expressed more in pancreatic head cancers (p = 0.026). CONCLUSIONS: Outcomes for ampullary cancers are better than for pancreatic head cancers. This different biological behavior can possibly be explained by differences in EGF-R expression.