Loss of ARID1A expression in colorectal carcinoma is strongly associated with mismatch repair deficiency

The Clinicopathologic Significance of BAF250a (ARID1A) Expression in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and lethal human cancers. Recently, exome sequencing has revealed that mutation of ARID1A is frequent in HCC. Herein, we determined the clinicopathologic significance of ARID1A expression in HCC. We detected the level of mRNA and protein expression of ARID1A in 12 paired HCC tumors and adjacent non-cancerous tissues by quantitative real-time PCR and immunohistochemistry (IHC). In addition, we determined the expression of BAF250a on 121 HCC tumors by IHC and assessed the association between BAF250a expression and clinicopathologic and prognostic features. The levels of ARID1A mRNA were significantly elevated in 10 of 12 HCC tumors compared with adjacent non-cancerous tissues. The level of BAF250a protein expression was higher in 10 of 12 HCC tumors compared with adjacent liver tissues. IHC indicated that 12.17 % of HCC tumors (14/115) were BAF250a-negative. Loss of BAF250a was significantly associated with larger tumor size, but not associated with other clinicopathologic features. There was no significant difference in disease-free or overall survival between BAF250a-positive and BAF250a-negative patients. Most HCCs had an increased level of ARID1A mRNA and BAF250a expression. Loss of BAF250a was significantly more frequent in larger HCC tumors, but had no prognostic significance.

Patterns of chromosomal copy-number alterations in intrahepatic cholangiocarcinoma

Background

Intrahepatic cholangiocarcinomas (ICC) are relatively rare malignant tumors associated with a poor prognosis. Recent studies using genome-wide sequencing technologies have mainly focused on identifying new driver mutations. There is nevertheless a need to investigate the spectrum of copy number aberrations in order to identify potential target genes in the altered chromosomal regions. The aim of this study was to characterize the patterns of chromosomal copy-number alterations (CNAs) in ICC.

Methods

53 patients having ICC with frozen material were selected. In 47 cases, DNA hybridization has been performed on a genomewide SNP array. A procedure with a segmentation step and a calling step classified genomic regions into copy-number aberration states. We identified the exclusively amplified and deleted recurrent genomic areas. These areas are those showing the highest estimated propensity level for copy loss (resp. copy gain) together with the lowest level for copy gain (resp. copy loss). We investigated ICC clustering. We analyzed the relationships between CNAs and clinico-pathological characteristics.

Results

The overall genomic profile of ICC showed many alterations with higher rates for the deletions. Exclusively deleted genomic areas were 1p, 3p and 14q. The main exclusively amplified genomic areas were 1q, 7p, 7q and 8q. Based on the exclusively deleted/amplified genomic areas, a clustering analysis identified three tumors groups: the first group characterized by copy loss of 1p and copy gain of 7p, the second group characterized by 1p and 3p copy losses without 7p copy gain, the last group characterized mainly by very few CNAs. From univariate analyses, the number of tumors, the size of the largest tumor and the stage were significantly associated with shorter time recurrence. We found no relationship between the number of altered cytobands or tumor groups and time to recurrence.

Conclusion

This study describes the spectrum of chromosomal aberrations across the whole genome. Some of the recurrent exclusive CNAs harbor candidate target genes. Despite the absence of correlation between CNAs and clinico-pathological characteristics, the co-occurence of 7p gain and 1p loss in a subgroup of patients may suggest a differential activation of EGFR and its downstream pathways, which may have a potential effect on targeted therapies.

Loss of ARID1A expression is associated with poor prognosis in small intestinal carcinoma

AIMS

To investigate AT-rich interactive domain-containing protein 1A (ARID1A) and p53 expression in small intestinal carcinoma (SIC) and to determine its prognostic significance.

METHODS AND RESULTS

Immunohistochemical staining for ARID1A and p53 was performed in 178 SICs using a tissue microarray (TMA). Loss of or low ARID1A expression was observed in 36 (20.2%) and 60 (33.7%) of cases, respectively. Aberrant p53 expression was observed in 99 (55.6%) cases. Loss of or low ARID1A expression was found to be associated with signet ring cell carcinoma and undifferentiated carcinoma, a high-grade tumour, and a higher T stage. No relationship was found between aberrant p53 expression and clinicopathological factors or overall survival. Patients with loss of ARID1A expression, irrespective of p53 expressional status, showed significantly poorer overall survival than those expressing ARID1A. Multiple regression analysis revealed that grade and pT stage were associated significantly with ARID1A loss, and multivariate analysis showed that patients with high ARID1A expression had a lower risk of death than those with loss of ARID1A expression.

CONCLUSIONS

Low or loss of ARID1A expression is correlated significantly with a high-grade tumour, higher T stage, and poorer overall survival. These findings suggest that ARID1A expression could be used as a prognostic marker in SIC.

Medullary colorectal carcinoma revisited: a clinical and pathological study of 102 cases

AIM

Medullary carcinoma is a recently described subtype of mismatch repair deficient (MMRd) colorectal carcinoma (CRC) which, despite being poorly differentiated by traditional morphological criteria, has been reported to have a good prognosis. We investigated the pathological and clinical features of medullary CRC in an unselected cohort of CRCs undergoing surgical resection.

METHODS

All CRCs resected within a single health district database from 1998 to 2012 were categorized prospectively and underwent retrospective review to identify 91 medullary CRCs, with 11 additional cases from 2013 to 2014. Strict criteria were employed to diagnose medullary carcinoma requiring both MMRd and greater than 90 % of the tumor to demonstrate typical morphology, including solid growth. The demographic and pathological features, as well as all-cause survival, were compared with other CRCs, and specifically to other MMRd CRCs.

RESULTS

From 1998 to 2012, 91 of 3,295 CRCs (2.8 %) were of the medullary type. Medullary CRC was more likely to arise in females than males (3.3:1; p < 0.0001), the elderly (mean age 77 vs. 71 years; p < 0.001), and the right colon (86 %; p < 0.0001). All medullary CRCs demonstrated MMR deficiency (considered an inclusion criteria) and 86 % were BRAFV600E-mutated (p < 0.0001). Thirty-day mortality after resection was higher in medullary CRC (4.6 vs. 1.7 %; p = 0.049). On univariate analysis, survival was not better than well-differentiated or other MMRd tumors. However, using a multivariate model, a medullary phenotype was protective (hazard ratio of death 0.54, 95 % CI 0.30-0.96; p = 0.037).

CONCLUSIONS

Medullary CRC is more common than previously reported, frequently presents with locally advanced disease, and may be associated with higher mortality at 30 days after resection. Despite this, when strict criteria are used for diagnosis, the overall survival is favorable when compared with CRCs with equivalent demographic and pathological characteristics.

Loss of AT-rich interactive domain 1A expression in gastrointestinal malignancies

OBJECTIVE

AT-rich interactive domain 1A (ARID1A) has recently been identified as a novel tumor suppressor in various tumor types. This study was designed to explore the clinical relevance and prognostic impact of ARID1A expression loss in colorectal cancer (CRC) and gastric cancer (GC).

METHODS

Immunohistochemistry for ARID1A was performed using tissue microarray blocks containing 196 CRCs and 275 GCs, along with paired normal mucosa. Data on clinicopathologic variables and oncologic outcomes of patients were collected and analyzed.

RESULTS

We identified 6.1% (12/196) CRC and 8.0% (22/275) GC cases showing loss of ARID1A expression. Expression of ARID1A in paired mucosal epithelial cells was normal in all patients. Loss of ARID1A expression was significantly correlated with negative lymphatic invasion (p = 0.003) in CRC, with large tumor size (p = 0.037) in GC, and with expanding tumor border in both tumor types (CRC, p = 0.010; GC, p = 0.031). However, no association was evident between ARID1A expression and 5-year overall survival in both tumor types.

CONCLUSIONS

Loss of ARID1A expression is uncommon and not associated with oncologic outcome but may be related to less invasive clinicopathologic features in CRC and GC. Further studies with a larger number of subjects are needed to establish the possible prognostic impact of ARID1A expression loss.

The expanding family of SMARCB1(INI1)-deficient neoplasia: implications of phenotypic, biological, and molecular heterogeneity

Since the description of atypical teratoid/rhabdoid tumors of the central nervous system and renal/extrarenal malignant rhabdoid tumors in children, the clinicopathologic spectrum of neoplasms having in common a highly variable rhabdoid cell component (0% to 100%) and consistent loss of nuclear SMARCB1 (INI1) expression has been steadily expanding to include cribriform neuroepithelial tumor of the ventricle, renal medullary carcinoma and a subset of collecting duct carcinoma, epithelioid sarcoma, subsets of miscellaneous benign and malignant soft tissue tumors, and rare rhabdoid carcinoma variants of gastroenteropancreatic, sinonasal, and genitourinary tract origin. Although a majority of SMARCB1-deficient neoplasms arise de novo, the origin of SMARCB1-deficient neoplasia in the background of a phenotypically or genetically definable differentiated SMARCB1-intact "parent neoplasm" has been convincingly demonstrated, highlighting the rare occurrence of rhabdoid tumors as "double-hit neoplasia." As a group, SMARCB1-deficient neoplasms occur over a wide age range (0 to 80 y), may be devoid of rhabdoid cells or display uniform rhabdoid morphology, and follow a clinical course that varies from benign to highly aggressive causing death within a few months irrespective of aggressive multimodality therapy. Generally applicable criteria that would permit easy recognition of these uncommon neoplasms do not exist. Diagnosis is based on site-specific and entity-specific sets of clinicopathologic, immunophenotypic, and/or molecular criteria. SMARCB1 immunohistochemistry has emerged as a valuable tool in confirming or screening for SMARCB1-deficient neoplasms. This review summarizes the different phenotypic and topographic subgroups of SMARCB1-deficient neoplasms including sporadic and familial, benign and malignant, and rhabdoid and nonrhabdoid variants, highlighting their phenotypic heterogeneity and molecular complexity.