Objective:To explore the values of reticulin fiber staining (RFS) in evaluating bone marrow (BM) involvement of lymphoma and in grading of BM biopsy from adult lymphoma patients.Methods:Retrospectively,354 cases of adult lymphoma were collected from November 2023 to May 2024 at Peking University Cancer Hospital. BM samples were stained with RFS and immunohistochemical staining (IHC), and flow cytometry (FCM) was also performed with the BM aspirations simultaneously. RFS was graded according to the European Consensus, as high grade (grade 2-3) indicating BM involvement in the study. BM involvement was considered as definite if no less than two positive findings among IHC, FCM, and RFS. Statistical analyses were performed via SPSS software (V23.0).Results:In this series, 52.3% (185/354) of the patients were male; 35.0% (124/354) aged >60 years; BM involvements were found in 34.5% (122/354) cases with high grade of RFS, which, in turn, were lymphoblastic leukemia/lymphoma (ALL/LBL) group (4/4), indolent B-cell lymphoma (IndBCL) group (49.1%, 53/108), transformed B-cell lymphoma (TrBCL) group (2/5), invasive B-cell lymphoma (InvBCL) group (26.5%, 41/155), T and NK cell lymphoma (TNKCL) group (27.3%, 12/44) and classical Hodgkin lymphoma (CHL) group (26.3%, 10/38); if classified by specific types, T-ALL/LBL (2/2), B-ALL/LBL (2/2) and CLL/SLL (8/10) ranked top three. In terms of the positive rate of BM involvement evaluated by RFS, no significant difference was seen between either gender or age groups ( χ2=3.416, P=0.332 and χ2=4.200, P=0.241); however, significant differences were observed between different lymphoma groups and types ( χ2=29.961, P=0.012 and χ2=102.546, P<0.001, respectively). BM invasion rates indicated by IHC and FCM were 25.4% (90/354) and 13.8% (49/354), respectively. The overall BM invasion rate was 24.3% (86/354), and the sensitivity of RFS, IHC, and FCM was 90.8%, 97.8%, and 55.8%, and specificity was 84.1%, 99.6%, and 98.9%, respectively. Overall, the concordance rate of RFS with IHC and FCM was 83.6% and 74.0%, respectively, including 85.8% and 74.2% for InvBCL group, 79.6% and 75.0% for IndBCL group, 84.1% and 75.0% for TNKCL group, 81.6% and 73.7% for CHL group, 5/5 and 2/5 for TrBCL group, and 4/4 and 3/4 for ALL/LBL group. Conclusions:In the evaluation of BM involvement status of adult lymphoma, high sensitivity and specificity are observed by RFS, and high concordance is also noted with both IHC and FCM. Thus, the BM infiltrating status of adult lymphoma could be evaluated more accurately by a combined usage of the three methods.

Objective:To explore the values of reticulin fiber staining (RFS) in evaluating bone marrow (BM) involvement of lymphoma and in grading of BM biopsy from adult lymphoma patients.Methods:Retrospectively,354 cases of adult lymphoma were collected from November 2023 to May 2024 at Peking University Cancer Hospital. BM samples were stained with RFS and immunohistochemical staining (IHC), and flow cytometry (FCM) was also performed with the BM aspirations simultaneously. RFS was graded according to the European Consensus, as high grade (grade 2-3) indicating BM involvement in the study. BM involvement was considered as definite if no less than two positive findings among IHC, FCM, and RFS. Statistical analyses were performed via SPSS software (V23.0).Results:In this series, 52.3% (185/354) of the patients were male; 35.0% (124/354) aged >60 years; BM involvements were found in 34.5% (122/354) cases with high grade of RFS, which, in turn, were lymphoblastic leukemia/lymphoma (ALL/LBL) group (4/4), indolent B-cell lymphoma (IndBCL) group (49.1%, 53/108), transformed B-cell lymphoma (TrBCL) group (2/5), invasive B-cell lymphoma (InvBCL) group (26.5%, 41/155), T and NK cell lymphoma (TNKCL) group (27.3%, 12/44) and classical Hodgkin lymphoma (CHL) group (26.3%, 10/38); if classified by specific types, T-ALL/LBL (2/2), B-ALL/LBL (2/2) and CLL/SLL (8/10) ranked top three. In terms of the positive rate of BM involvement evaluated by RFS, no significant difference was seen between either gender or age groups ( χ2=3.416, P=0.332 and χ2=4.200, P=0.241); however, significant differences were observed between different lymphoma groups and types ( χ2=29.961, P=0.012 and χ2=102.546, P<0.001, respectively). BM invasion rates indicated by IHC and FCM were 25.4% (90/354) and 13.8% (49/354), respectively. The overall BM invasion rate was 24.3% (86/354), and the sensitivity of RFS, IHC, and FCM was 90.8%, 97.8%, and 55.8%, and specificity was 84.1%, 99.6%, and 98.9%, respectively. Overall, the concordance rate of RFS with IHC and FCM was 83.6% and 74.0%, respectively, including 85.8% and 74.2% for InvBCL group, 79.6% and 75.0% for IndBCL group, 84.1% and 75.0% for TNKCL group, 81.6% and 73.7% for CHL group, 5/5 and 2/5 for TrBCL group, and 4/4 and 3/4 for ALL/LBL group. Conclusions:In the evaluation of BM involvement status of adult lymphoma, high sensitivity and specificity are observed by RFS, and high concordance is also noted with both IHC and FCM. Thus, the BM infiltrating status of adult lymphoma could be evaluated more accurately by a combined usage of the three methods.

Objective:To study the clinicopathological features and PD-L1 expression of microsatellite instability-high (MSI-H) gastric cancer.Methods:The clinicopathological data of the 2 472 patients who had undergone radical surgical resection and been performed immunohistochemical staining of four major mismatch repair (MMR) proteins (MLH1, PMS2, MSH2 and MSH6) from March 2014 to December 2018 at Peking University Cancer Hospital were collected. One hundred and seventy-one patients showed mismatch repair-deficient (dMMR), and microsatellite instability of these patients were detected with polymerase chain reaction (PCR). Then, taken PCR results as the standard, PD-L1 was assessed using immunohistochemistry (IHC) in the MSI-H gastric cancers.Results:MSI-H (vs. MSI-L) in gastric cancers was associated with female gender, advanced age, gastric-antrum location, intestinal type, lesion diameter exceeding 5 cm, absence of lymph node metastasis and positive PD-L1 expression ( P<0.05, respectively). Combined positive score (CPS) was an independent risk factor ( P=0.026, HR=8.385, 95% CI=1.293-54.367). Although no relationship between PD-L1 expression pattern and prognosis was observed,"diffuse-pattern" of the PD-L1 expression was related to lymphatic-vascular invasion ( P=0.007) and infiltration depth ( P=0.04). Among the patients with MSI-H and PD-L1 positive gastric cancer, the patients who experienced recurrence or died all had the pattern of "diffuse" PD-L1 expression. Also, regarding the expression level and staining pattern of PD-L1, the metastasis lesion of lymph node had a high coincidence with primary site ( P=0.45). Conclusions:MSI-H gastric cancer shows distinctive clinicopathological characteristics. The CPS can be used as a prognostic indicator in MSI-H gastric cancers, while the "diffuse-pattern" of PD-L1 expression could possibly be used as a prognostic indicator. The patients with advanced gastric cancer could obtain the expression level and staining pattern of PD-L1 using the biopsy material of metastatic lesions.