Expression of tumor suppressor and tumor-related proteins in differentiated carcinoma, undifferentiated carcinoma with tubular component and pure undifferentiated carcinoma of the stomach

Histogenetic insights and genetic landscape of fibromatosis-like undifferentiated gastric carcinoma: a focused study

BACKGROUND

The aim of this study was to elucidate the histogenesis and genetic underpinnings of fibromatosis-like undifferentiated gastric carcinoma (FLUGC), a rare pathological entity.

METHOD

Through a detailed analysis of seven cases, including histopathological evaluation, CTNNB1 gene mutation screening, human epidermal growth factor receptor 2 (HER2) protein level quantification, and HER2 gene amplification assessment to identify the pathological and molecular characteristics of FLUGC.

RESULTS

Of the seven patients in this study, five were male and two were female (age: 39-73 years). Four patients presented with lesions in the gastric antrum and three had lesions in the lateral curvature of the stomach. Histopathologically, over 90% of the tumor consisted of aggressive fibromatosis-like tissue, including proliferating spindle fibroblasts and myofibroblasts and varying amounts of collagenous fibrous tissues. Undifferentiated cancer cells, accounting for less than 10%, were dispersed among the aggressive fibromatosis-like tissues. These cells were characterized by their small size and were relatively sparse without glandular ducts or nested mass-like structures. Immunophenotyping results showed positive expression of CKpan, CDX2, villin, and p53 in undifferentiated cancer cells; positive expression of vimentin in aggressive fibromatosis-like tissue; positive cytoplasmic expression of β-catenin; and focal cytoplasmic positive expression of smooth muscle actin (SMA). Genetic analysis did not reveal any mutations in the CTNNB1 gene test, nor was there amplification in the HER2 gene fluorescence in situ hybridization (FISH) test. Additionally, the Epstein-Barr encoding region (EBER) of in situ hybridization was negative; and the mismatch repair (MMR) protein was positive. Programmed cell death-1 (PD-1) was < 1-5%; programmed cell death ligand 1 (PD-L1): TPS = 1-4%, CPS = 3-8.

CONCLUSION

The study highlights the significance of CTNNB1, HER2, EBER, and MMR as pivotal genetic markers in FLUGC, underscoring their relevance for diagnosis and clinical management. The rarity and distinct pathological features of FLUGC emphasize the importance of accurate diagnosis to prevent underdiagnosis or misdiagnosis and to raise awareness within the medical community.

Helicobacter pylori modulated host immunity in gastric cancer patients with S-1 adjuvant chemotherapy

BACKGROUND

Paradoxically, Helicobacter pylori-positive (HP+) advanced gastric cancer patients have a better prognosis than those who are HP-negative (HP-). Immunologic and statistical analyses can be used to verify whether systemic mechanisms modulated by HP are involved in this more favorable outcome.

METHODS

A total of 658 advanced gastric cancer patients who underwent gastrectomy were enrolled. HP infection, mismatch repair, programmed death-ligand 1 (PD-L1), and CD4/CD8 proteins, and microsatellite instability were analyzed. Overall survival (OS) and relapse free survival (RFS) rates were analyzed after stratifying clinicopathological factors. Cox proportional hazards regression analysis was performed to identify independent prognostic factors.

RESULTS

Among 491 cases that were analyzed, 175 (36%) and 316 (64%) cases were HP+ and HP⁻, respectively. Analysis of RFS indicated an interaction of HP status among the subgroups for S-1 dose (Pinteraction=0.0487) and PD-L1 (P = .016). HP+ patients in the PD-L1⁻ group had significantly higher five-year OS and RFS than HP- patients (81% vs. 68%; P = .0011; HR 0.477; 95% CI, 0.303-0.751 and 76% vs. 63% P = .0011; HR 0.508; 95% CI, 0.335-0.771, respectively). The five-year OS and RFS was also significantly higher for HP+ compared to HP- patients in the PD-L1-/S-1-reduced group (86% vs. 46%; P = .0014; HR 0.205; 95% CI, 0.07-0.602 and 83% vs. 34%; P = .001; HR 0.190; 95% CI, 0.072-0.498, respectively). Thus, HP status was identified as one of the most potentially important independent factors to predict prolonged survival.

CONCLUSION

This retrospective study suggests that an HP-modulated host immune system may contribute to prolonged survival in the absence of immune escape mechanisms of gastric cancer.

Clinicopathological features and differential diagnosis of gastrofibromatosis-like undifferentiated carcinoma

Objective

To study the clinicopathological features and differential diagnosis of gastrofibromatosis-like undifferentiated carcinoma (GFLUC).

Methods

Three patients with GFLUC underwent histological and immunophenotypic analyses and fluorescence in situ hybridization to detect human epidermal growth factor receptor (HER2) gene amplification.

Results

Among the three patients (2 male [36 and 44 years old], 1 female [58 years old]), two had lesions in the gastric body and one had lesions in the gastric antrum. Histological analysis revealed mixtures of aggressive fibromatosis and undifferentiated carcinoma in all three cases. Highly invasive fibromatous tissue, consisting of fibroblasts, proliferating myofibroblasts, and collagenous fibrous tissues, accounted for >90% of the tumor, with undifferentiated cancerous tissue accounting for <10% scattered in the gaps within the invasive fibromatous tissue, with no glandular ducts or nests. Immunophenotypic analysis showed that the undifferentiated cancerous cells were positive for pan-cytokeratin, CDX2, villin, and p53, while the cytoplasm of invasive fibromatous cells was positive for vimentin, β-catenin, and smooth muscle actin. No HER2 gene amplification was detected.

Conclusions

Unlike other gastric carcinomas, GFLUC shows specific histological, biological, and immunophenotypic characteristics.

Analysis of PIK3CA mutations and PI3K pathway proteins in advanced gastric cancer

BACKGROUND

Although surgery and chemotherapy have extended advanced gastric cancer patient survival, some patients still experience relapse and metastasis. We postulated that PI3K pathway proteins could be prognostic biomarkers for the advanced gastric cancer patients.

METHODS

A retrospective cohort of 160 advanced gastric cancer patients receiving potentially curative surgery with/without chemotherapy was investigated for PIK3CA mutation and PI3K pathway protein level in the context of overall survival and relapse-free survival.

RESULTS

Thirteen patients (13 of 111, 11.7%) had PIK3CA mutations in codon 545, whereas one patient (1 of 94, 1.1%) had a mutation in PIK3CA codon 1047. PI3K pathway protein immunohistochemistry demonstrated that phosphorylated AKT positive [p-AKT (+)] patients in the surgery-only group had a good prognosis in terms of overall survival and relapse-free survival. No significant association between PIK3CA mutations and PI3K pathway protein level was seen.

CONCLUSIONS

This study revealed that (1) PIK3CA hotspot mutations occurred with low frequency in gastric cancer; (2) PIK3CA hotspot mutations were not directly associated with PI3K pathway activation; and (3) p-AKT (+) may be a biomarker for better outcomes for gastric cancer patients undergoing gastrectomy regardless of the PIK3CA mutation status.

Mixed Carcinoma as an Independent Prognostic Factor in Submucosal Invasive Gastric Carcinoma

Mixed carcinoma shows a mixture of glandular and signet ring/poorly cohesive cellular histological components and the prognostic significance of each component is not fully understood. This study aimed to investigate the significance of the poorly cohesive cellular histological component as a risk factor for lymph node metastasis and to examine the diagnostic reliability of endoscopic biopsy. Clinicopathologic characteristics of 202 patients who underwent submucosal invasive gastric carcinoma resection with lymph node dissection in 2005-2012 were reviewed. Mixed carcinoma accounted for 27.2% (56/202) of cases. The overall prevalence of lymph node metastasis was 17.3% (35/202). Lymphatic invasion (P < 0.001), family history of carcinoma (P = 0.025), tumor size (P = 0.004), Lauren classification (P = 0.042), and presence of any poorly cohesive cellular histological component (P = 0.021) positively correlated with the lymph node metastasis rate on univariate analysis. Multivariate analyses revealed lymphatic invasion, family history of any carcinoma, and the presence of any poorly cohesive cellular histological component to be significant and independent factors related to lymph node metastasis. Review of preoperative biopsy slides showed that preoperative biopsy demonstrated a sensitivity of 63.6% and a specificity of 100% in detecting the presence of the poorly cohesive cellular histological component, compared with gastrectomy specimens. The presence of any poorly cohesive cellular histological component was an independent risk factor associated with lymph node metastasis in submucosal invasive gastric carcinoma. Endoscopic biopsy had limited value in predicting the presence and proportion of the poorly cohesive cellular histologic component due to the heterogeneity of mixed carcinoma.

Molecular marker identification for relapse prediction in 5-FU-based adjuvant chemotherapy in gastric and colorectal cancers

To confirm the clinical significance of NF-κB and JNK protein expression from experimentally identified candidates for predicting prognosis for patients with 5-FU treatment, we evaluated the protein expression of surgically removed specimens. A total of 79 specimens were obtained from 30 gastric and 49 colorectal cancer patients who underwent R0 resection followed by postoperative 5-FU based adjuvant chemotherapy. Immunohistochemical examinations of NF-κB and JNK on tissue microarrays (TMAs) revealed that significantly shorter time-to-relapse (TTR) in both NF-κB(+) and JNK(−) subgroups in both gastric (NF-κB(+), p = 0.0002, HR11.7. 95%CI3 3.2–43.4; JNK(−), p = 0.0302, HR4.4, 95%CI 1.2–16.6) and colon (NF-κB(+), p = 0.0038, HR36.9, 95%CI 3.2–426.0; JNK(−), p = 0.0098, HR3.2, 95%CI 1.3–7.7) cancers. These protein expression patterns also show strong discriminately power in gastric cancer patients for overall survival rate, suggesting a potential utility as prognostic or chemosensitivity markers. Baseline expression of these proteins using gastric cancer cell lines demonstrated the reciprocal patterns between NF-κB and JNK, while 5-FU exposure of these cell lines only induced NF-κB, suggesting that NF-κB plays a dominant role in the response to 5-FU. Subsequent siRNA experiments confirmed that gene knockdown of NF-κB increased 5-FU-specific sensitivity, whereas that of JNK did not affect the chemosensitivity. These results suggest that the expression of these proteins may aid in the decisions involved with adjuvant chemotherapy for gastrointestinal tract cancers.

Expression of PTEN and P16 proteins in varioliform gastritis and gastric cancer

AIM: To explore the relationship between varioliform gastritis and gastric cancer.

METHODS: The expression of PTEN and P16 proteins in chronic superficial gastritis, varioliform gastritis and gastric cancer was detected by immunohistochemistry.

RESULTS: The positive rate of PTEN protein expression in varioliform gastritis was significantly lower than that in chronic superficial gastritis (44.4% vs 92%, χ² = 14.47, P < 0.01) though no significant difference was noted between varioliform gastritis and gastric cancer (44.4% vs 25.8%, χ² = 2.51, P > 0.05). The positive rate of P16 protein expression in varioliform gastritis was significantly lower than that in chronic superficial gastritis (50% vs 96%, χ² = 14.56, P < 0.01), but significantly higher than that in gastric cancer (50% vs 19.4%, χ² = 6.80, P < 0.01).

CONCLUSION: Both PTEN and P16 proteins may be involved in the evolution of varioliform gastritis to gastric cancer.

Canine gastric carcinoma: immunohistochemical expression of cell cycle proteins (p53, p21, and p16) and heat shock proteins (Hsp27 and Hsp70)

Immunohistochemical staining for cell cycle proteins and heat shock proteins was performed on 17 canine gastric carcinomas. The immunoexpression of p53, p21, p16, Hsp27, and Hsp70 was investigated. A study was conducted to determine the histological type and parameters related to tumor malignancy. Possible associations and trends were assessed between the immunoexpression of each protein and tumor type as well as specific parameters of malignancy. High intratumor frequency of cellular p53 immunostaining was observed (61.96% average), but lower frequencies of p21 and p16 expression were present (34.65% and 10.41%, respectively). The p53 overexpression was associated with tumor infiltration (P = .0258). Expression of p21 was lower in undifferentiated carcinomas, and the loss of expression was associated with histopathological parameters characteristic of a poor prognosis such as lymphatic vessel invasion (P = .0258). The lack of p16 immunoreactivity was related to histopathological characteristics of malignancy such as the presence of evident and multiple nucleoli (P = .0475). In contrast, deep tumor infiltration was observed in those carcinomas with a high p16 index (P = .0475). Hsp70 appeared to be overexpressed in all gastric neoplasms included in this study. This is in contrast to Hsp27, because a group of tumors showed complete lack of Hsp27 immunoexpression, whereas the others displayed extensive Hsp27 immunostaining. The differences in Hsp27 did not correlate with any of the histopathological parameters, but Hsp27 immunoexpression was higher in the undifferentiated carcinoma. No significant differences in the expression of the proteins were found in canine gastric carcinomas according to their histological type. These findings may be useful for establishing a prognosis for canine gastric carcinoma.

CDKN2A promoter methylation is related to the tumor location and histological subtype and associated with Helicobacter pylori flaA(+) strains in gastric adenocarcinomas

Promoter hypermethylation of CDKN2A (p16INK4A protein) is the main mechanism of gene inactivation. However, its association with Helicobacter pylori infection is a controversial issue. Therefore, we examined a series of gastric adenocarcinomas to assess the association between p16INK4A inactivation and H. pylori genotype (vacA, cagA, cagE, virB11 and flaA) according to the location and histological subtype of the tumors. p16INK4A expression and CDKN2A promoter methylation were found in 77 gastric adenocarcinoma samples by immunohistochemistry and methylation-specific PCR, respectively. Helicobacter pylori infection and genotype were determined by PCR. A strong negative correlation between immunostaining and CDKN2A promoter region methylation was found. In diffuse subtype tumors, the inactivation of p16INK4A by promoter methylation was unique in noncardia tumors (p=0.022). In addition, H. pylori-bearing flaA was associated with non-methylation tumors (p=0.008) and H. pylori strain bearing cagA or vacAs1m1 genes but without flaA was associated with methylated tumors (p=0.022 and 0.003, respectively). Inactivation of p16INK4A in intestinal and diffuse subtypes showed distinct carcinogenic pathways, depending on the tumor location. Moreover, the process of methylation of the CDKN2A promoter seems to depend on the H. pylori genotype. The present data suggest that there is a differential influence and relevance of H. pylori genotype in gastric cancer development.

Immunohistochemical differential diagnosis between thymic carcinoma and type B3 thymoma: diagnostic utility of hypoxic marker, GLUT-1, in thymic epithelial neoplasms

There are only a few immunohistochemical markers that are useful for differentiating thymic carcinomas from type B3 thymomas. The purpose of this study is to examine the additional markers that would be useful for differentiating between thymic carcinoma and thymoma type B3. We performed a tissue microarray analysis of surgically resected thymic tumor specimens from 12 cases of thymic carcinoma, 7 cases of type B3 thymoma, and 68 cases of other types of thymoma. Immunostaining using 49 antibodies was scored based on staining intensity and the percentage of cells that stained positive. Seven proteins that were selected by the staining scores, namely, GLUT-1 (167 vs 4), CA-IX (110 vs 15), c-kit (162 vs 44), CD5 (33 vs 0), MUC-1 (54 vs 0), CEA (42 vs 0), and CK18 (110 vs 42), were significantly higher in the thymic carcinomas than in the type B3 thymomas. The staining sensitivity and specificity of the antibodies for thymic carcinoma were GLUT-1, sensitivity 72% and specificity 100%; CA-IX, 58 and 71%; c-kit, 72 and 85%; CD5, 33 and 100%; CK18, 58 and 71%; MUC-1, 25 and 100%; and CEA, 33 and 100%. Glucose transporter 1 (GLUT-1) is the best marker for thymic carcinoma because it had the highest sensitivity and specificity. Positive immunostaining for a combination of three markers, namely, GLUT-1, CD5, and CEA, enabled differentiation of thymic carcinoma with 91.6% sensitivity and 100% specificity. In conclusion, we identified GLUT-1 as an additional marker that will be useful for differentiating thymic carcinoma from type B3 thymoma, especially in biopsy specimens that have been crushed or are otherwise difficult to examine morphologically in thymic tumors.

Abnormal expression of p16(INK4a), cyclin D1, cyclin-dependent kinase 4 and retinoblastoma protein in gastric carcinomas

BACKGROUND AND OBJECTIVES

The p16(INK4a) (p16), cyclin D1, cyclin-dependent kinase (CDK) 4 and retinoblastoma (Rb) genes are components of the Rb pathway that controls the G1-S checkpoint of the cell cycle. The aim of this study was to assess the relationship between their abnormalities and clinicopathological features in gastric carcinomas.

METHODS

Immunohistochemical analysis of the encoded proteins was performed on a series of 158 cases.

RESULTS

Loss of p16/Rb protein (pRb) expression and overexpression of cyclin D1/CDK4 were observed in 49%/40% and 37%/37% of gastric carcinomas, respectively. At least 1 of these abnormalities was found in 86% of the cases and a positive correlation was noted between p16 and pRb (P = 0.009). Cyclin D1 (P = 0.042) and CDK4 (P = 0.008) overexpession was inversely associated with lymph node metastasis and depth of invasion, respectively. Loss of pRb expression was more frequently in diffuse type lesions than in the intestinal type (P = 0.022). The patients with p16+/pRb-/cyclin D1-/CDK4- or p16-/pRb+/cyclin D1-/CDK4- tumors demonstrated particularly poor survival. With multivariate survival analysis, only depth of invasion and TNM stage could be proven as independent predictors.

CONCLUSIONS

The Rb pathway is disrupted in the vast majority of gastric carcinomas. This study also identified specific immunohistochemical marker profiles for prognosis.

Detection of micrometastases in sentinel node navigation surgery for gastric cancer

Although lymph node metastasis is one of the important prognostic factors for patients with gastric cancer, the clinical significance of micrometastasis remains controversial. In the 6th edition of the TMN classification, micrometastases were classified as micrometastasis (MM) and isolated tumor cells (ITC) according to its greatest dimension. The accurate diagnosis of micrometastases is required when considering less invasive surgery, especially in early stage of gastric cancer. Since generating useful information about micrometastases by conventional RT-PCR is time-consuming, this procedure is not useful for rapid diagnosis during surgery. Recently some new methods of genetic diagnosis have reduced the amount of time required to obtain information about micrometastases in lymph nodes to 30-40 min. Such methodology can be clinically applied during less invasive surgery. The sentinel node (SN) concept has recently been applied to gastric cancer and SN navigation surgery (SNNS) is ideal for reduction of lymphadenectomy in patients with early gastric cancer. However, we should think about some conditions to establish SN concept for gastric cancer: the particle size of radioisotope, relationship between metastatic area and RI uptake, and the diagnosis of micrometastases by various method such as histological examination, immunostaining and RT-PCR. Here, we described the current status of MM and ITC in the lymph nodes and the SN concept in gastric cancer.

Molecular staging of gastric cancer

Gastric cancer has traditionally been staged using purely histological methods, but these methods provide little information about the biology of gastric cancer and have limited predictive power. Recent studies have shown that clinically relevant gastric cancer subtypes have distinct gene expression profiles. This approach, termed molecular staging, can lead to the discovery of novel diagnostic and prognostic biomarkers of gastric cancers. This update reviews advances in molecular staging of gastric cancer and discusses their implications for the prognosis and diagnosis of this complex disease. Technologies used in molecular staging as well as future directions for the optimization of molecular staging of gastric cancer are also discussed.

Immunohistochemical biomarkers of value in distinguishing primary ovarian carcinoma from gastric carcinoma: a systematic review with statistical meta-analysis

AIMS

To compare the relative risk of antigen expression being detected immunohistochemically in ovarian and gastric carcinoma aggregated from studies performed for diagnostic purposes, with the relative risks of their expression in all patients in the English literature.

METHODS AND RESULTS

Both types of series indicated that cytokeratin (CK) 7 expression was greater and that of CK20 and carcinoembryonic antigen less in ovarian than in gastric carcinoma (P < 0.05). Synthesis of all data available for MUC-2 suggested it was more commonly expressed in ovarian carcinoma, whereas the relative risk in papers that directly compared its expression suggested that it was more common in the gastric carcinoma (P = 0.2, NS). Aggregating all possible data suggested villin was more likely to be expressed in ovarian cancers, whereas studies in which its expression was compared directly in both tumours suggested the opposite. Although statistically significant, patient numbers were small.

CONCLUSION

Provided sufficient numbers of cases are studied, analysis of studies comparing antigen expression for diagnostic purposes in tumours from two body sites is likely to be supported in the wider literature. The design of such comparative studies is informed by aggregating data from single tumour studies.