Immunohistochemistry and scoring of Ki-67 proliferative index and p53 expression in gastric B cell lymphoma from Northern African population: a pilot study

Accurate interpretation of p53 immunohistochemical patterns is a surrogate biomarker for TP53 alterations in large B-cell lymphoma

BACKGROUND

To clarify the relationship between p53 immunohistochemistry (IHC) staining and TP53 alterations (including mutations and deletions) in large B-cell lymphomas (LBCLs) and to explore the possibility of p53 IHC expression patterns as surrogate markers for TP53 alterations.

METHODS

A total of 95 patients diagnosed with LBCLs were selected, and paraffin samples were taken for TP53 gene sequencing, fluorescence in situ hybridization and p53 IHC staining. The results were interpreted by experienced pathologists and molecular pathologists.

RESULTS

Forty-three nonsynonymous TP53 mutations and p53 deletions were detected in 40 cases, whereas the remaining 55 cases had wild-type TP53 genes. The majority of TP53 mutations (34/43, 79.1%) occurred in exons 4-8, and R248Q was the most common mutation codon (4/43, 9.3%). The highest frequency single nucleotide variant was C > T (43.6%). p53 expression was interpreted as follows: Pattern A: p53 staining was positive in 0%-3% of tumor cells, Pattern B: p53 staining was positive in 4-65% of tumor cells, Pattern C: more than 65% of tumor cells were stained positive for p53. The p53 IHC expression patterns were associated with TP53 alterations. Gain of function variants and wild-type TP53 tended to exhibit type C and B p53 expression patterns, but loss of function variants were exclusively seen in type A cases. Additionally, interpretation of the staining by various observers produced significant reproducibility.

CONCLUSIONS

The p53 IHC expression patterns can be used to predict TP53 alterations and are reliable for diverse alteration types, making them possible surrogate biomarkers for TP53 alterations in LBCLs.

Study of the Utility of Myeloid Cell Nuclear Differentiation Antigen (MNDA) in the Diagnosis of Marginal Zone Lymphoma

Myeloid cell nuclear differentiation antigen (MNDA) is normally expressed on myelomonocytic cells and a subset of B lymphocytes. It was found to be differentially expressed between nodal marginal zone lymphoma (MZL) and follicular lymphoma (FL). However, MNDA has not been widely used as a diagnostic marker in clinical practice. To validate its utility, we studied the expression of MNDA by immunohistochemistry in 313 cases of small B-cell lymphomas. Our results showed that MNDA was positive in 77.9% of MZL, 21.9% of mantle cell lymphoma, 28.9% of small lymphocytic lymphoma/chronic lymphocytic leukemia, 2.6% of FL, and 25% of lymphoplasmacytic lymphoma. MNDA positivity varied from 68.0% to 84.0% among the 3 MZL subtypes, with extranodal MZL having the highest percentage. There was a statistically significant difference in MNDA expression between MZL and FL, mantle cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia, or lymphoplasmacytic lymphoma. CD43 expression was slightly more frequent in MNDA-negative MZL than in MNDA-positive MZL. Combined use of CD43 and MNDA improved the diagnostic sensitivity for MZL from 77.9% to 87.8%. There was a trend of positive correlation between MNDA and p53 in MZL. In conclusion, MNDA is preferentially expressed in MZL among small B-cell lymphomas and it is a useful marker for the differentiation of MZL and FL.

Ileal mucosa-associated lymphoid tissue lymphoma diagnosed after emergency surgery: A case report and literature review

Introduction and importance

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, also called MALT lymphoma, is one of the entities of marginal zone lymphomas. These lymphomas are originated from indolent B-cell lymphomas and involve many organs such as the gastrointestinal tract, salivary gland, skin, lung, thyroid or breast. Ileal MALT lymphoma is relatively rare and clinical symptoms are usually atypical.

Case presentation

We report a case of a 99-year-old man who admitted to the emergency department with increasing and colicky periumbilical pain, vomiting and constipation. Non-contrast-enhanced computed tomography suggested small bowel obstruction due to phytobezoar. Intraoperatively, surgeon discovered the tumor at the site of phytobezoar. Histologically, there was a diffuse infiltration comprised of small to medium sized lymphocytes with monocytoid features. Immunohistochemical result confirmed CD20 positive B-lymphocytes and the Ki-67 proliferation index was 10%. Ileal mucosa-associated lymphoid tissue lymphoma was diagnosed based on histological findings and immunohistochemistry.

Discussion

MALToma of the gastrointestinal tract is related to chronic antigenic, inflammatory bowel disease and malabsorption syndromes. However, the etiology of ileal MALToma is unclear. Moreover, symptom of ileal MALToma is really not typical and overleaped in the context of small intestinal obstruction. It should be differentiated small intestinal MALToma from immunoproliferative small intestinal disease and an alpha heavy chain disease.

Conclusion

Ileal MALT lymphoma remains little known in many previous studies. It is really difficult to preoperatively diagnose. The combination of clinical presentation, postoperative histology and immunohistochemistry contribute to diagnosis and carry out appropriate management.

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Ileal MALT lymphoma is relatively rare compared to others gastrointestinal MALT lymphomas and symptoms are usually atypical.

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A 99-year-old man was hospitalized with the symptoms of bowel obstruction.

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Emergency surgery, postoperative histology and immunohistochemistry confirmed ileal MALT lymphoma.

A systematic review of primary gastric diffuse large B-cell lymphoma: Clinical diagnosis, staging, treatment and prognostic factors

Primary gastric lymphoma (PGL) is a rare clinical entity accounting for the majority of extra-nodal non-Hodgkin lymphoma (EN-NHL). The most common histological subtype is the primary gastric diffuse large B-cell lymphoma (PG-DLBCL) with a media age of 50-60 years old, mostly in male. Pathogenesis is often related to some bacterial infection such as Helicobacter pylori (H. pylori) infection. However, due to various available staging system, there is still no consensus on the staging of PG-DLBCL. The international prognostic index (IPI) is the most valuable used for the stratification of almost all subtype of NHL and as well as for PG-DLBCL. As for treatment strategies, surgery, chemotherapy, radiation therapy and antibiotic therapy in various combinations have been applied in clinical treatment. There are a few well-known prognostic factors and some of them may constitute prognostic models. Due to the increasing incidence of this neoplasm, it is necessary for clinicians to make deep insight of the diagnosis, staging, treatment and prognostic factors of PG-DLBCL.

CTLA-4 immunotherapy exposes differences in immune response along with different tumor progression in colorectal cancer

Tumor growth is accompanied by a changing tumor microenvironment and mutations that increase the resistance to therapy. Here, we used syngeneic models to evaluate the drug response of tumors of the same type of different sizes. We used the in vivo efficacy and Ki-67 immunohistochemistry (IHC) assay to assess the difference in responses in response to treatment with the same concentration of anti-CTLA-4. Flow cytometry analysis revealed changes in the immune subpopulations changes the spleen, peripheral blood, lymph node, and tumor tissue across different tumor growth phases. For example, naive CD4+T, CD4+TCM, CD8+TEM, T, B, Treg, CD8+TCM exhibited different percentages depending on the specific immune organ. To further expose the changes in the immune microenvironment, the level of expression of PD-1 and CTLA-4 showed statistically significant difference in related subsets for each four immune tissues in different tumor sizes. In addition, the ratios of CD4 + Teff/ CD4 + Treg and CD8 + T/Treg in corresponding immune tissue were also associated with statistically significant differences alongside tumor growth in different animal models. These results reveal the ongoing changes in the immune microenvironment during tumor progression and anti-CTLA-4 antibody immunotherapy effect depends on the expression level of immune factors.

Molecular Subtypes, Apoptosis and Proliferation Status in Indonesian Diffuse Large B-Cell Lymphoma Cases

Objective:

The diffuse large B-cell lymphoma (DLBCL) has two major molecular subtypes, germinal center B-cell-like (GCB) and non-GCB. These have differing behavior which affects overall patient survival. However, immunohistochemistry based molecular subtyping of Indonesian DLBCLs has been limited. This was the focus of the present study, with a focus of attention on the apoptotic index (AI) and the proliferation index (PI) of the two molecular subtypes.

Materials and Methods:

During the study period of 3.5 years, a total of 98 cases of DLBCL were identified. Molecular subtypes and PI were determined by immunohistochemistry and TUNEL method was used to determine the AI.

Result:

GCB accounted for 31 cases (31.6%) and non-GCB the remainder (68.4%). Gender showed a slight male predominance (54 cases, 55.1%), with a higher incidence in the extra-nodal region (57 cases, 58.2%). The AI and PI were significantly higher in GCB (p<0.001 in the Mann-Whitney test) and a Spearman correlation coefficient test showed that PI was positively correlated with AI (r=0.673, p<0.001).

Conclusion:

The findings indicate that the non-GCB subtype is more common than GCB in Indonesian DLBCL. GCB features significantly higher PI and AI, which themselves appear linked.

Highly selective peroxisome proliferator-activated receptor δ (PPARδ) modulator demonstrates improved safety profile compared to GW501516

Compound 1 regulates significantly fewer genes than the PPARδ modulator, GW501516. Both compounds are efficacious in a thermal injury model of muscle regeneration. The restricted gene profile of 1 relative to GW501516 suggests that 1 may be pharmacoequivalent to GW501516 with fewer PPAR-related safety concerns.