Poroma is a benign skin tumor exhibiting terminal sweat gland duct differentiation. The present study aimed to explore the potential role of gene fusions in the tumorigenesis of poromas. RNA ...sequencing and reverse transcription PCR identified highly recurrent YAP1-MAML2 and YAP1-NUTM1 fusions in poromas (92/104 lesions, 88.5%) and their rare malignant counterpart, porocarcinomas (7/11 lesions, 63.6%). A WWTR1-NUTM1 fusion was identified in a single lesion of poroma. Fluorescent in-situ hybridization confirmed genomic rearrangements involving these genetic loci. Immunohistochemical staining could readily identify the YAP1 fusion products as nuclear expression of the N-terminal portion of YAP1 with a lack of the C-terminal portion. YAP1 and WWTR1, also known as YAP and TAZ, respectively, encode paralogous transcriptional activators of TEAD, which are negatively regulated by the Hippo signaling pathway. The YAP1 and WWTR1 fusions strongly transactivated a TEAD reporter and promoted anchorage-independent growth, confirming their tumorigenic roles. Our results demonstrate the frequent presence of transforming YAP1 fusions in poromas and porocarcinomas and suggest YAP1/TEAD-dependent transcription as a candidate therapeutic target against porocarcinoma.
Background
We are increasingly experiencing difficulty in deciding whether to perform gastrectomy after noncurative endoscopic resection of early gastric cancer (EGC) for patients at high risk for ...surgery. If the differences in risk for lymph node metastasis (LNM) on the basis of noncurative status are understood, the decision becomes easier. The present study aimed to stratify the LNM risk and develop and validate a risk-scoring model for predicting LNM.
Methods
By retrospectively reviewing 3131 patients with solitary EGC who underwent gastrectomy with lymphadenectomy at our institution between July 1997 and May 2013, LNM risk was stratified and a risk-scoring model was developed on the basis of the identified independent risk factors for LNM. The scoring was validated using 352 other surgically resected EGC cases. The discriminatory accuracy of the scoring was measured by area under receiver operating characteristic curve (AUROC).
Results
LNM was detected in 386 of 3131 cases. LNM risk in each subgroup, stratified by the identified independent risk factors, such as tumor size, depth, histological type, ulcerative findings, and lymphovascular involvement, considerably varied from 0 % to >50 % even among the current guidelines’ noncurative subgroups. An 11-point scoring model was built, and AUROCs were 0.84 (95 % confidence interval, 0.82–0.86) and 0.82 (0.75–0.88) in the development and validation sets, respectively.
Conclusions
The present study revealed detailed LNM risk stratification data, and developed and validated an 11-point scoring model.
Background
The heterotopic submucosal gland (HSG) is a common incidental finding in gastrectomy specimens. The majority of HSGs are small incidental lesions, which are also known as gastritis cystica ...profunda. However, larger lesions may appear as an inverted growth of well-organized mucosa referred to as gastric inverted polyps.
Methods
To determine whether genetic alterations are involved in HSG development, we analyzed 63 gastric HSG lesions using targeted next-generation sequencing and immunohistochemistry.
Results
Histologically, HSG lesions consistently had areas of pyloric gland differentiation with variable extent of foveolar differentiation. Although the background mucosa showed intestinal metaplasia in most cases (98%), intestinal-type epithelium was seen in only one HSG lesion (2%). Sequencing analysis identified activating
KRAS
,
BRAF
,
CTNNB1
, and
GNAS
mutations in 34 (54%), 1 (2%), 1 (2%), and 7 (11%) lesions, respectively. HSG lesions harboring a
KRAS
mutation were more likely to present extensive foveolar differentiation (
P
= 0.013) and absence of parietal cells (
P
= 0.0081). Five HSG lesions had a dysplastic component, and concordant genetic alterations were detected between the non-dysplastic and dysplastic areas of two lesions that were successfully analyzed. Immunohistochemical staining demonstrated diffuse expression of mutant KRAS protein in lesions with the most common genetic alteration,
KRAS
G12D.
Conclusions
Our study demonstrated that a major proportion of HSGs were proliferative lesions associated with oncogenic mutations, with more than half of lesions harboring activating
KRAS
mutations.
Background
Traditional serrated adenoma (TSA) is the least common type of colorectal serrated polyp, which exhibits considerable morphological and molecular diversity.
Methods
We examined the spectra ...of alterations in MAPK and WNT pathway genes and their relationship with clinicopathological features in 128 TSAs.
Results
Sequencing analyses identified
BRAF
V600E,
BRAF
non-V600E,
KRAS
, and
NRAS
mutations in 77, 3, 45, and 1 lesion, respectively. Collectively, 124 lesions (97%) had mutations in MAPK pathway genes. Alterations in WNT pathway genes were identified in 107 lesions (84%), including
RSPO
fusions/overexpression,
RNF43
mutations,
ZNRF3
mutations,
APC
mutations, and
CTNNB1
mutations in 47, 45, 2, 13, and 2 lesions, respectively. Ten lesions (8%) harbored
GNAS
mutations. There was significant interdependence between the altered MAPK and WNT pathway genes.
RSPO
fusions/overexpression was significantly associated with
KRAS
mutations (31/47, 66%), whereas most
RNF43
mutations coexisted with the
BRAF
V600E mutation (40/45, 89%). Histologically, extensive slit-like serration was more common in lesions with the
BRAF
V600E mutation (71%) and those with
RNF43
mutations (87%). Prominent ectopic crypt formation was more prevalent in lesions with
RSPO
fusions/overexpression (58%) and those with
GNAS
mutations (100%).
Conclusions
Our observations indicate that TSAs mostly harbor various combinations of concurrent WNT and MAPK gene alterations. The associations between genetic and morphological features suggest that the histological diversity of TSA reflects the underlying molecular heterogeneity.
Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no ...unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns-immature, intermediate and mature-using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study.
Background
Automated image analysis has been developed currently in the field of surgical pathology. The aim of the present study was to evaluate the classification accuracy of the e-Pathologist ...image analysis software.
Methods
A total of 3062 gastric biopsy specimens were consecutively obtained and stained. The specimen slides were anonymized and digitized. At least two experienced gastrointestinal pathologists evaluated each slide for pathological diagnosis. We compared the three-tier (positive for carcinoma or suspicion of carcinoma; caution for adenoma or suspicion of a neoplastic lesion; or negative for a neoplastic lesion) or two-tier (negative or non-negative) classification results of human pathologists and of the e-Pathologist.
Results
Of 3062 cases, 33.4% showed an abnormal finding. For the three-tier classification, the overall concordance rate was 55.6% (1702/3062). The kappa coefficient was 0.28 (95% CI, 0.26–0.30; fair agreement). For the negative biopsy specimens, the concordance rate was 90.6% (1033/1140), but for the positive biopsy specimens, the concordance rate was less than 50%. For the two-tier classification, the sensitivity, specificity, positive predictive value, and negative predictive value were 89.5% (95% CI, 87.5–91.4%), 50.7% (95% CI, 48.5–52.9%), 47.7% (95% CI, 45.4–49.9%), and 90.6% (95% CI, 88.8–92.2%), respectively.
Conclusions
Although there are limitations and requirements for applying automated histopathological classification of gastric biopsy specimens in the clinical setting, the results of the present study are promising.
Cancer-associated fibroblasts (CAFs), a major component of cancer stroma, can confer aggressive properties to cancer cells by secreting multiple factors. Their phenotypes are stably maintained, but ...the mechanisms are not fully understood. We aimed to show the critical role of epigenetic changes in CAFs in maintaining their tumour-promoting capacity and to show the validity of the epigenomic approach in identifying therapeutic targets from CAFs to starve cancer cells.
Twelve pairs of primary gastric CAFs and their corresponding non-CAFs (NCAFs) were established from surgical specimens. Genome-wide DNA methylation and H3K27me3 analyses were conducted by BeadArray 450K and ChIP-on-Chip, respectively. Functions of potential a therapeutic target were analysed by inhibiting it, and prognostic impact was assessed in a database.
CAFs had diverse and distinct DNA methylation and H3K27me3 patterns compared with NCAFs. Loss of H3K27me3, but not DNA methylation, in CAFs was enriched for genes involved in stem cell niche, cell growth, tissue development and stromal-epithelial interactions, such as
,
,
and
. Among these, we revealed that WNT5A, which had been considered to be derived from cancer cells, was highly expressed in cancer stromal fibroblasts, and was associated with poor prognosis. Inhibition of secreted WNT5A from CAFs suppressed cancer cell growth and migration.
H3K27me3 plays a crucial role in defining tumour-promoting capacities of CAFs, and multiple stem cell niche factors were secreted from CAFs due to loss of H3K27me3. The validity of the epigenetic approach to uncover therapeutic targets for cancer-starving therapy was demonstrated.
Cancer chemoresistance is often attributed to the presence of cancer stem cell (CSC)-like cells, but whether they are homogeneously chemoresistant remains unclear. We previously showed that in colon ...tumors, a subpopulation of
CSC-like cells driven by TCF1 (TCF7), a Wnt-responsive transcription factor, were responsible for tumorigenicity. Here we demonstrate that the tumorigenic subpopulation of mouse
cells exists in a slow-cycling state and identify a unique 22-gene signature that characterizes these slow-cycling CSC. Seven of the signature genes are specifically expressed in slow-cycling
cells from xenografted human colon tumors and are upregulated in colon cancer clinical specimens. Among these seven, four genes (
, and
) are known to be direct Wnt target genes, and
was expressed in the invasive fronts of colon tumors.
was activated by TCF1 to induce CDKN1C and maintain a slow-cycling state in colon cancer organoids. Strikingly, PROX1 was required for recurrent growth after chemotherapeutic treatment, suggesting that inhibition of slow-cycling CSC by targeting the TCF1-PROX1-CDKN1C pathway is an effective strategy to combat refractory colon cancer in combination with conventional chemotherapy. SIGNIFICANCE: These findings illustrate the importance of a slow-cycling CSC subpopulation in colon cancer development and chemoresistance, with potential implications for the identified slow-cycling CSC signatures and the TCF1-PROX1-CDKN1C pathway as therapeutic targets.
Organoids derived from epithelial tumors have recently been utilized as a preclinical model in basic and translational studies. This model is considered to represent the original tumor in terms of 3D ...structure, genetic and cellular heterogeneity, but not tumor microenvironment. In this study, we established organoids and paired cancer-associated fibroblasts (CAFs) from surgical specimens of colorectal carcinomas (CRCs), and evaluated gene expression profiles in organoids with and without co-culture with CAFs to assess interactions between tumor cells and CAFs in tumor tissues. We found that the expression levels of several genes, which are highly expressed in original CRC tissues, were downregulated in organoids but re-expressed in organoids by co-culturing with CAFs. They comprised immune response- and external stimulus-related genes, e.g., REG family and dual oxidases (DUOXs), which are known to have malignant functions, leading tumor cells to proliferative and/or anti-apoptotic states and drug resistant phenotypes. In addition, the degree of differential induction of REG1 and DUOX2 in the co-culture system varied depending on CAFs from each CRC case. In conclusion, the co-culture system of CRC organoids with paired CAFs was able to partially reproduce the tumor microenvironment.
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