Short-course radiotherapy combined with CAPOX and PD-1 inhibitor for the total neoadjuvant therapy of locally advanced rectal cancer: the preliminary single-center findings of a prospective, multicentre, randomized phase II trial (TORCH) / 中华胃肠外科杂志

Objective: Total neoadjuvant therapy has been used to improve tumor responses and prevent distant metastases in patients with locally advanced rectal cancer (LARC). Patients with complete clinical responses (cCR) then have the option of choosing a watch and wait (W&W) strategy and organ preservation. It has recently been shown that hypofractionated radiotherapy has better synergistic effects with PD-1/PD-L1 inhibitors than does conventionally fractionated radiotherapy, increasing the sensitivity of microsatellite stable (MSS) colorectal cancer to immunotherapy. Thus, in this trial we aimed to determine whether total neoadjuvant therapy comprising short-course radiotherapy (SCRT) combined with a PD-1 inhibitor improves the degree of tumor regression in patients with LARC. Methods: TORCH is a prospective, multicenter, randomized, phase II trial (TORCH Registration No. NCT04518280). Patients with LARC (T3-4/N+M0, distance from anus ≤10 cm) are eligible and are randomly assigned to consolidation or induction arms. Those in the consolidation arm receive SCRT (25Gy/5 Fx), followed by six cycles of toripalimab plus capecitabine and oxaliplatin (ToriCAPOX). Those in the induction arm receive two cycles of ToriCAPOX, then undergo SCRT, followed by four cycles of ToriCAPOX. Patients in both groups undergo total mesorectal excision (TME) or can choose a W&W strategy if cCR has been achieved. The primary endpoint is the complete response rate (CR, pathological complete response [pCR] plus continuous cCR for more than 1 year). The secondary endpoints include rates of Grade 3-4 acute adverse effects (AEs) etc. Results: Up to 30 September 2022, 62 patients attending our center were enrolled (Consolidation arm: 34, Induction arm:28). Their median age was 53 (27-69) years. Fifty-nine of them had MSS/pMMR type cancer (95.2%), and only three MSI-H/dMMR. Additionally, 55 patients (88.7%) had Stage III disease. The following important characteristics were distributed as follows: lower location (≤5 cm from anus, 48/62, 77.4%), deeper invasion by primary lesion (cT4 7/62, 11.3%; mesorectal fascia involved 17/62, 27.4%), and high risk of distant metastasis (cN2 26/62, 41.9%; EMVI+ 11/62, 17.7%). All 62 patients completed the SCRT and at least five cycles of ToriCAPOX, 52/62 (83.9%) completing six cycles of ToriCAPOX. Finally, 29 patients achieved cCR (46.8%, 29/62), 18 of whom decided to adopt a W&W strategy. TME was performed on 32 patients. Pathological examination showed 18 had achieved pCR, four TRG 1, and 10 TRG 2-3. The three patients with MSI-H disease all achieved cCR. One of these patients was found to have pCR after surgery whereas the other two adopted a W&W strategy. Thus, the pCR and CR rates were 56.2% (18/32) and 58.1% (36/62), respectively. The TRG 0-1 rate was 68.8% (22/32). The most common non-hematologic AEs were poor appetite (49/60, 81.7%), numbness (49/60, 81.7%), nausea (47/60, 78.3%) and asthenia (43/60, 71.7%); two patients did not complete this survey. The most common hematologic AEs were thrombocytopenia (48/62, 77.4%), anemia (47/62, 75.8%), leukopenia/neutropenia (44/62, 71.0%) and high transaminase (39/62, 62.9%). The main Grade III-IV AE was thrombocytopenia (22/62, 35.5%), with three patients (3/62, 4.8%) having Grade IV thrombocytopenia. No Grade V AEs were noted. Conclusions: SCRT-based total neoadjuvant therapy combined with toripalimab can achieve a surprisingly good CR rate in patients with LARC and thus has the potential to offer new treatment options for organ preservation in patients with MSS and lower-location rectal cancer. Meanwhile, the preliminary findings of a single center show good tolerability, the main Grade III-IV AE being thrombocytopenia. The significant efficacy and long-term prognostic benefit need to be determined by further follow-up.

Role of arginase-1 expression in distinguishing hepatocellular carcinoma from non-hepatocellular tumors / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the role of arginase-1 (Arg-1) expression in differential diagnosis of hepatocellular carcinoma (HCC), Arg-1 staining pattern in clear cell neoplasm (HCC and non-HCC) and Arg-1 expression in non-hepatocellular tumors.</p><p><b>METHODS</b>Seventy-eight cases of HCC (including 8 cases of clear cell type and 70 cases of non- clear cell type) and 246 cases of non-hepatocellular neoplasms (including 29 cases of metastatic tumors such as breast cancer, nasopharyngeal carcinoma and neuroendocrine carcinoma, 77 cases of tumors with clear cell changes such as malignant melanoma, clear cell renal cell carcinoma and alveolar soft part sarcoma, and 140 cases of other types of tumors such as ovarian endometrioid adenocarcinoma, pituitary tumor and thyroid papillary carcinoma) were studied.Immunohistochemical study for Arg-1 was performed on the paraffin-embedded tumor tissue.</p><p><b>RESULTS</b>In HCC, Arg-1 demonstrated both cytoplasmic and nuclear staining, with an overall sensitivity of 96.2% (75/78).In well, moderately and poorly differentiated HCC, the sensitivity was 15/15, 100% (41/41) and 86.4% (19/22), respectively. That was in contrast to negative staining for Arg-1 in all the 29 cases of metastatic tumors studied. The sensitivity, specificity, positive predictive value and negative predictive value of Arg-1 in distinguishing HCC from metastatic tumors was 96.2%, 100%, 100% and 90.6%, respectively. Cytoplasmic and membranous staining was observed in clear cell type of HCC. The overall sensitivity of Arg-1 expression in the 77 cases of tumors with clear cell changes was 14.3% (11/77), including 8/15 for malignant melanoma, 2/4 for ovarian clear cell carcinoma and 1/1 gall bladder adenocarcinoma with clear cell component.In malignant melanoma and ovarian clear cell carcinoma, only cytoplasmic staining was demonstrated. There was no expression of Arg-1 in the 140 cases of other tumor types studied.</p><p><b>CONCLUSIONS</b>Arg-1 is a sensitive and specific marker for HCC.It is a potentially useful immunohistochemical marker in distinguishing HCC from metastatic tumors. Though also expressed in malignant melanoma and ovarian clear cell carcinoma, Arg-1 shows a different staining pattern as compared with that in HCC.</p>

Detection of chromosomal translocations involving ALK gene in anaplastic large cell lymphoma by fluorescence in-situ hybridization and its clinical significance / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate clinicopathologic features and clinical value of the chromosomal translocation involving anaplastic lymphoma kinase (ALK) in anaplastic large cell lymphoma (ALCL) by fluorescence in situ hybridization (FISH).</p><p><b>METHODS</b>A total of 55 cases, including 45 cases of ALCL and 10 reactive lymphoid hyperplasia, were collected during 1999 to 2006 in the Department of Pathology, Fudan University Shanghai Cancer Center, and Xinhua Hospital Affiliated to Shanghai Jiaotong University. All cases were studied by FISH using dual color break apart probes of ALK for detection of chromosomal translocation, compared with the previous results of immunohistochemistry (IHC) and reverse-transcriptase polymerase chain reaction (RT-PCR) for the detection of ALK aberrations.</p><p><b>RESULTS</b>The result of FISH showed that the clear red and green fluorescence signals were detected in 38 cases of ALCL, in which conspicuous split signals were observed in tumor cells in 24 cases (63.2%), suggesting the rearrangement of the ALK locus, with multiple copies of ALK gene in one case. In addition, the rearrangement of the ALK locus was not identified in 14 of 38 cases (36.8%); and the FISH results were unable to be evaluated in 7 cases, because no fluorescent signals involving ALK gene were found or signals were too weak to be analyzed. The concordance for the detection ALK aberrations in ALCL between FISH and RT-PCR, FISH and IHC were both statistically significant (P < 0.01). Chromosomal translocation involving ALK gene was not found in all 10 cases of reactive lymphoid hyperplasia.</p><p><b>CONCLUSIONS</b>ALCL is an entity of lymphoma characterized by special clinical presentation, morphology, and ALK aberrations. FISH is helpful for detection of the chromosomal translocations involving ALK in ALCL, however, the detection efficiency by FISH may be affected by storage time of the paraffin-embedded tissue; and therefore combined detection with IHC and RT-PCR could complement each other and help for differential diagnosis of ALK(+)ALCL from ALK(-)ALCL.</p>

Myxoid dermatofibrosarcoma protuberans: a clinicopathologic analysis of 16 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features and differential diagnosis of myxoid dermafibrosarcoma protuberans (DFSP).</p><p><b>METHODS</b>The clinical and pathologic features of 16 cases of myxoid DFSP were reviewed.</p><p><b>RESULTS</b>There were altogether 15 males and 1 female. The age of the patients ranged from 11 to 73 years (mean = 47 years and median = 48 years). The commonest site of involvement was trunk (number = 11), followed by shoulder (number = 2), head and neck (number = 2), and extremity (number = 1). Similar to conventional DFSP, most patients presented with a slowly enlarging subcutaneous nodule which showed a rapid recent growth in some cases. Amongst the 16 cases studied, 12 occurred de novo and 4 represented local recurrence. The tumors ranged from 2 to 10 cm in greatest dimension (mean = 5 cm and median = 4 cm). Histologically, they were poorly circumscribed and located in the dermis, with focal infiltration into the underlying subcutaneous tissue. Seven cases were purely myxoid and composed of spindly and stellate cells with delicate arborizing vascular meshwork. The remaining 9 cases were predominantly myxoid (> 50%), with 5 cases containing cellular areas resembling conventional DFSP and 4 cases showing fibrosarcomatous transformation. In addition, foci of giant cell fibroblastoma-like areas were noted in 1 case. Immunohistochemical study showed that the tumors cells were positive for CD34. The staining was weak in the myxoid areas, as compared with conventional DFSP. Of the 4 recurrent cases, one patient developed lung metastases.</p><p><b>CONCLUSIONS</b>Myxoid DFSP represents a rare variant of DFSP and may pose important diagnostic pitfalls. It is especially so if the tumor purely consists of myxoid element. Familiarity with the histologic features helps to avoid misdiagnosis.</p>

KRAS and BRAF gene mutations in correlation with clinicopathologic features of colorectal carcinoma in Chinese / 中华病理学杂志

<p><b>OBJECTIVE</b>To retrospectively analyze KRAS and BRAF gene mutation features in Chinese colorectal cancer (CRC) and their clinicopathologic relationship.</p><p><b>METHODS</b>557 colorectal cancer cases were collected, including 325 colon cancer and 232 rectal cancer. PCR amplification and DNA sequencing were used to detect mutations in exon 2 of KRAS gene and exon 15 of BRAF gene mutation.</p><p><b>RESULTS</b>(1) KRAS mutation was found in 40.4% (225/557) colorectal cancer. The most common mutation locations were in codon 12(79.1%, 178/225) and codon 13 (20.4%, 46/225). The most common mutation types were GGT > GAT (G12D) (37.8%, 85/225), GGT > GTT(G12V) (20.0%, 45/225) in codon 12 and GGC > GAC (G13D) in codon 13 (19.6%, 44/225). These three point mutations accounted 77.3% (174/225) in total KRAS gene mutation cases. All cases showed only one of point mutation types. (2) Among 557 CRC cases, KRAS mutation was significantly higher in female (46.2%, 92/199) than in man (37.2%, 133/358; P < 0.05). KRAS gene codon 13 mutation was higher in right colon cancer (11.3%, 12/106) than that in left colon cancer (4.8%, 6/124), but it didn't show any statistical significance (P > 0.05). (3) BRAF gene mutation was 5.1% (10/197) in colorectal cancer and 8/10 were the point mutation of GTG > GAG (V600E). Eight colorectal cancer cases with GTG > GAG (V600E) were not showing KRAS gene mutation. Both two cases with mutation on codon 600 (GTG > ATG, V600M) and codon 606 (GGG > AGT, G606S) showed codon 12 mutation of KRAS gene. (4) BRAF (V600E) gene mutation was higher in female (8.5%, 6/71) than that in male (1.6%, 2/126; P = 0.05); BRAF mutation in colon cancer (8.3%, 6/72) was higher than that in rectum cancer (2.1%, 2/94), but hadn't statistical significance (P > 0.05).</p><p><b>CONCLUSIONS</b>(1) Codon 12, 13 in KRAS gene and codon 600 in BRAF gene are the most common mutation points in Chinese colorectal cancer. KRAS and BRAF mutations are mutually exclusive. (2) KRAS and BRAF gene mutation is higher in female than that in male, suggesting that RAS-RAF-MAPK signal pathway is probably related to hormones directly or indirectly. (3) There is a trend that codon 13 mutation in KRAS and codon 600 mutation in BRAF in right colon cancer are higher than that in left colon cancer, respectively, however, which needs more cases to be further verified.</p>

Plexiform angiomyxoid myofibroblastic tumor of stomach / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features, immunophenotype and differential diagnosis of plexiform angiomyxoid myofibroblastic tumor (PAMT) of the stomach.</p><p><b>METHODS</b>The clinical and pathologic findings of 3 cases of PAMT in the gastric antrum were retrospectively analyzed. Immunohistochemical study was carried out and the literature was reviewed.</p><p><b>RESULTS</b>The age of patients ranged from 31 to 47 years. The male-to-female ratio was 1:2. The clinical presentation included epigastric pain and distension. Endoscopically, the tumor mass protruded into the gastric cavity at the antrum and ranged from 4.5 cm to 8.0 cm in greatest dimension. One of the tumors studied was associated with surface ulceration. Histologically, the tumors were located in the gastric wall. They were composed of bland spindle cells and small vessels arranged in a plexiform or nodular pattern within a myxoid stroma. Immunohistochemical study showed that the spindle cells were consistently positive for smooth muscle actin and muscle-specific actin. There was focal staining for h-caldesmon, desmin in case 3 and focal positive for epithelial membrane antigen, CAM5.2 in case 1. Further, CD10 and progesterone receptor were positive in case 3.</p><p><b>CONCLUSIONS</b>PAMT represents a rare novel mesenchymal tumor of the stomach, with a propensity of gastric antral involvement. The distinctive pathologic features help to differentiate this entity from other benign and malignant tumors.</p>

Prevalence of API2-MALT1 fusion gene in gastrointestinal mucosa-associated lymphoid tissue lymphomas and diffuse large B cell lymphomas / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the difference of the prevalence of t(11;18)(q21;q21)/API2-MALT1 fusion gene between gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B cell lymphoma (DLBCL).</p><p><b>METHODS</b>A total of 57 cases gastrointestinal MALT lymphomas (38 gastric and 19 intestinal lymphomas), 32 DLBCL (28 gastric and 4 intestinal lymphomas) and 7 cases gastric DLBCL accompanied MALT lymphoma were collected from the Cancer Hospital of Fudan University. API2-MALT1 fusion gene was detected by fluorescent in situ hybridization (FISH) using both dual fusion translocation and break apart probes.</p><p><b>RESULTS</b>Among gastrointestinal MALT lymphomas, API2-MALT1 fusion gene was found in 12 of 57 cases (21.1%, 10 gastric and 2 intestinal lymphomas). In contrast, the fusion gene was not found in all 32 DLBCL and 7 gastric DLBCL with MALT lymphoma component. There was statistical significant difference between two groups (chi(2) = 9.383, P = 0.001).</p><p><b>CONCLUSIONS</b>API2-MALT1 fusion gene is a distinctive genetic aberration in MALT lymphomas, and is not present in DLBCL. The findings suggest that gastrointestinal tract MALT lymphomas with API2-MALT1 fusion gene may not transform into DLBCL, which may represent primary lymphoma or transformed API2-MALT1 negative MALT lymphomas.</p>

Clinicopathologic study of intraabdominal extranodal follicular dendritic cell sarcoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features and immunophenotype of intraabdominal extranodal follicular dendritic cell sarcoma (FDCS) and the relationship with Epstein-Barr virus (EBV).</p><p><b>METHODS</b>The clinical and histologic features of 4 cases of FDCS were evaluated. Immunohistochemical study was performed using standard EnVision method for CD21, CD23, CD35, S-100 protein, CD68, HLA-DR, vimentin, epithelial membrane antigen, desmin, CD34 and CD117. In-situ hybridization for EBV-encoded RNA (EBER) was carried out in 2 cases.</p><p><b>RESULTS</b>The age of patients ranged from 28 to 63 years (mean=42 years). The male-to-female ratio was 3:1. The clinical presentation was abdominal discomfort, pain or mass. Radiologic examination revealed concurrent lesions in stomach and left lobe of liver in 1 patient, while non-specific intraabdominal masses were detected in the remaining cases (in which the tumor was later found to be located in the appendix, mesentery of jejunum and omentum). Two cases were misdiagnosed as gastrointestinal stromal tumor before operation. Grossly, the tumors appeared as large solid nodules, with a mean diameter of 10.8 cm. Three of the cases showed areas of necrosis. Histologically, there were plump spindle, ovoid to epithelioid cells associated with scattered multinucleated giant cells. The tumor cells were arranged mostly in storiform pattern, whorls, fascicles or solid sheets. Lymphocytic infiltrates with perivascular cuffing were noted in all cases, resulting in a distinctive biphasic pattern. Two tumors showed significant cytologic atypia, with mitotic figures (including atypical mitotic figures) readily demonstrated. The remaining case (occurring in liver) was composed of scattered large atypical cells embedded in a dense inflammatory background, mimicking inflammatory pseudotumor. Immunohistochemical study showed that all cases were positive for CD21, CD23 and vimentin. There was focal expression of CD35, S-100 protein, CD68, HLA-DR and epithelial membrane antigen. The staining for CD34 and CD117 was negative. In-situ hybridization for EBER was negative in 2 cases tested.</p><p><b>CONCLUSIONS</b>Intraabdominal extranodal FDCS is extremely rare. Familiarity with its characteristic histologic features and immunophenotype is important in distinguishing the tumor from other intraabdominal spindle cell lesions (such as gastrointestinal stromal tumor). Hepatic FDCS may show inflammatory pseudotumor-like features, resulting in misinterpretation. Non-hepatic intraabdominal FDCS seems to have little association with EBV infection.</p>