The chromatin remodelling component SMARCB1/INI1 influences the metastatic behavior of colorectal cancer through a gene signature mapping to chromosome 22.

BACKGROUND: INI1 (Integrase interactor 1), also known as SMARCB1, is the most studied subunit of chromatin remodelling complexes. Its role in colorectal tumorigenesis is not known. METHODS: We examined SMARCB1/INI1 protein expression in 134 cases of colorectal cancer (CRC) and 60 matched normal mucosa by using tissue microarrays and western blot and categorized the results according to mismatch repair status (MMR), CpG island methylator phenotype, biomarkers of tumor differentiation CDX2, CK20, vimentin and p53. We validated results in two independent data sets and in cultured CRC cell lines. RESULTS: Herein, we show that negative SMARCB1/INI1 expression (11% of CRCs) associates with loss of CDX2, poor differentiation, liver metastasis and shorter patients' survival regardless of the MMR status or tumor stage. Unexpectedly, even CRCs displaying diffuse nuclear INI1 staining (33%) show an adverse prognosis and vimentin over-expression, in comparison with the low expressing group (56%). The negative association of SMARCB1/INI1-lack of expression with a metastatic behavior is enhanced by the TP53 status. By interrogating global gene expression from two independent cohorts of 226 and 146 patients, we confirm the prognostic results and identify a gene signature characterized by SMARCB1/INI1 deregulation. Notably, the top genes of the signature (BCR, COMT, MIF) map on the long arm of chromosome 22 and are closely associated with SMARCB1/INI1. CONCLUSION: Our findings suggest that SMARCB1/INI1-dysregulation and genetic hot-spots on the long arm of chromosome 22 might play an important role in the CRC metastatic behavior and be clinically relevant as novel biomarkers.

KRAS mutations and M2PK upregulation in stool samples from individuals with positive fecal occult blood tests screened for colorectal cancer.

BACKGROUND: Screening for colorectal cancer (CRC) requires non-invasive methods of high diagnostic sensitivity and specificity. We evaluated the measurement of genetic and protein biomarkers of CRC in stool samples with the aim of testing their clinical utility in a CRC screening program. PATIENTS AND METHODS: Individuals aged 53-75 years who were at risk of CRC and immunochemical fecal occult blood test (iFOBT) positive were invited to submit stool samples for molecular testing prior to colonoscopy. KRAS codon 12 Gly→Asp, Gly, Val, and codon 13 Gly→Cys gene mutations were tested using an in-house real-time ARMS PCR method. M2PK levels in stool samples were measured utilizing a commercial ELISA kit. RESULTS: At colonoscopy, 7.6% of patients were found to have CRC, 50% had adenomas, 10.6% had hyperplastic polyps, 20.2% had diverticulosis and hemorrhoids, and 11.6% had normal mucosa. The best sensitivity for CRC (50%) was found in those cases where M2PK and KRAS abnormalities coexisted. M2PK showed a detection rate of 40.3% for adenomas but the combination of M2PK and KRAS abnormalities was found in only 5.7% of adenomas (P <0.01). iFOBT was false positive in 31.8% of cases in which colonoscopy excluded neoplastic lesions, while the coexistence of molecular and enzymatic abnormalities was more specific with false positive rates between 8.3% and 9.0% (P <0.05). CONCLUSION: Our molecular screening approach demonstrates that detection of cancer-associated biomarkers measured in iFOBT-positive stool samples could help separate true from false positives in a FOBT-based screening process. M2PK showed particular promise for the detection of CRC and adenomas.

Comparison between invasive breast cancer with extensive peritumoral vascular invasion and inflammatory breast carcinoma: a clinicopathologic study of 161 cases.

OBJECTIVES: Extensive peritumoral neoplastic lymphovascular invasion (ePVI) is a marker of aggressiveness in invasive breast carcinoma (BC). METHODS: We explored the impact of ePVI on different BC subtypes. In a total of 2,116 BCs, 91 ePVI-BCs, 70 inflammatory breast carcinomas (IBCs), and 114 casual BCs as a control group (CG-BC) were recruited. RESULTS: Patients affected by ePVI-BC were younger, had larger tumors, higher histologic grade, elevated Ki-67 score, Her2/neu overexpressed, and more lymph node metastases compared with CG-BC (P < .001). Interestingly, only younger mean age at diagnosis differentiated patients with ePVI-BC from patients affected by IBC. ePVI-BC showed a clinical outcome intermediate between the prognoses of IBC and CG-BC. CONCLUSIONS: Results suggest that ePVI-BC and IBC may share some pathologic processes, providing a novel perspective on the heterogeneity of BC. Epidemiologic data and molecular studies on gene expression features are needed to rationally classify these tumors into their identified subtypes.

Right-sided rhabdoid colorectal tumors might be related to the serrated pathway.

BACKGROUND: Rhabdoid colorectal tumor (RCT) is a rare, highly aggressive neoplasm recurrent in elderly patients, commonly at the caecum. The molecular mechanisms underlying RCT pathogenesis remain poorly elucidated. The differential diagnosis is with the malignant rhabdoid tumors of infancy characterized by genetic inactivation of SMARCB1 (INI1) or deletions of chromosome 22q12 locus. MATERIALS AND METHODS: To shed light on RCT pathogenesis, we investigated genetic and epigenetic alterations in two cases of pure and composite RCT and compared them with the profiles of matched adenomas and normal mucosa. Immunohistochemical analysis, FISH, methylation specific PCR and DNA sequencing analysis were performed on paraffin-embedded tissues. RESULTS: Loss of epithelial markers, (CK20, CDX2 and E-cadherin) and intense vimentin expression was observed in RCTs but neither in the normal mucosa or adenomas. INI1 expression was detected in normal mucosa, adenomas and retained in pure RCT, while it was undetected in composite RCT. Rearrangement of the 22q12 locus was found only in pure RCT. The APC/ß-catenin pathway was not altered, while MLH1 immunostaining was negative in RCTs and positive in adenomas and normal mucosa. These expression profiles were associated with V600E BRAF mutation, a progressive accumulation of promoter methylation at specific CIMP loci and additional genes from the normal mucosa to tubular adenoma and RCT. CONCLUSIONS: Right-sided RCT could be characterized by epigenetic events and molecular features likely similar to those occurring in the serrated pathway and associated with epithelial-mesenchymal transition. These extremely rare tumors may benefit from the use of new biological molecules specific for colorectal carcinoma. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1641385210804556.

Rhabdoid carcinoma of the colon: a distinct entity with a very aggressive behavior: a case report associated with a polyposis coli and review of the literature.

Rhabdoid colon tumors (RCTs) are rare lesions whose existence as an independent distinct entity remains controversial. To date, 6 RCTs have been reported. This study reports a novel case associated with polyposis coli in a 73-year-old woman. Histologically, the neoplasia was heterogeneous consisting of an adenocarcinoma associated with rhabdoid features. In rhabdoid component, an intense expression of MSH2 was noted but MLH1 was negative. A BRAF V600E mutation and no KRAS mutations were identified. The promoter regions of subset of genes highly specific to characterize the CIMP status (NEUROG1, IGF2, RUNX3, SOCS1, including MLH1) were hypermethylated, suggesting the presence of CIMP+ and MSI high tumor. In conclusion, all RCTs have similar clinical features. The presence of polyposis and adenocarcinoma component as well as the expression of mesenchymal marker suggests a sarcomatous dedifferentiation. It is argued that RCT could be a very aggressive entity of colon, which could benefit from new biological colonic treatments.

Fine-needle cytology of cutaneous juvenile xanthogranuloma and langerhans cell histiocytosis.

BACKGROUND: In pediatric patients, a cutaneous nodule is usually diagnosed by performing an excisional biopsy, but fine-needle cytology (FNC) is a safer and noninvasive diagnostic method widely used to obtain diagnostic specimens with little stress to the patient. The authors compared the ability of FNC and biopsy to differentiate Langerhans cell histiocytosis (LCH) from juvenile xanthogranuloma (JXG). METHODS: Correlating cytological results with histological findings, the authors reviewed 27 patients (15 males and 12 females; mean age, 37 months; range, 1 month to 14 years) admitted to the University of Padua Department of Pediatrics from 1998 to 2010. RESULTS: Cytology smears were adequate in all 27 (100%) patients: 14 (52%) were classified as having JXG, 12 (44%) as having LCH, and 1 (4%) as having a doubtful finding. A biopsy was also performed in 20 of these patients, and in all but 1, the 2 methods were completely concordant. CONCLUSIONS: FNC is safe and useful in the diagnostic workup of pediatric patients with cutaneous nodules and has no contraindications to its use as the initial diagnostic procedure.