PD-L1 Overexpression in the Lungs of Subjects Who Died from COVID-19: Are We on the Way to Understanding the Immune System Exhaustion Induced by SARS-CoV-2?

Knowledge of the pathogenic mechanisms of severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2) is certainly a priority for the scientific community. Two main elements are involved in the biology of the most severe forms of coronavirus disease 2019 (COVID-19): the direct cytopathic effect of the virus against the host tissues, and a dysfunction of the immune system, characterized by the exhaustion of T lymphocytes. The exhaustion of T cells in COVID-19 is poorly understand, but some data could suggest a possible role of PD-1/PD-L1 axis. The aim of this study was to evaluate the possible role of PD-L1 expression in the pulmonary tissue in subjects affected by COVID-19. The presence of SARS-CoV-2 in the pulmonary tissue, and its exact location, was indagated by in situ hybridization; the expression of PD-L1 and CD8 in the same tissue was indagated by immunohistochemistry. Overall, PD-L1 resulted diffusely expressed in 70% of the cases, and an intense expression was observed in 43.5% of cases. Diffuse and intense presence of SARS-CoV-2 by in situ hybridization significantly correlated with an intense PD-L1 expression, and with expression of PD-L1 by pneumocytes. PD-L1 is overexpressed in the pulmonary tissue of subjects died from COVID-19, and mainly in subjects with a high viral load. These data suggest a possible role of PD-L1 in the immune system exhaustion at the basis of the severe forms of the disease.

Variable levels of spike and ORF1ab RNA in post-mortem lung samples of SARS-CoV-2-positive subjects: comparison between ISH and RT-PCR.

Post-mortem examination plays a pivotal role in understanding the pathobiology of the SARS-CoV-2; thus, the optimization of virus detection on the post-mortem formalin-fixed paraffin-embedded (FFPE) tissue is needed. Different techniques are available for the identification of the SARS-CoV-2, including reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), in situ hybridization (ISH), and electron microscopy. The main goal of this study is to compare ISH versus RT-PCR to detect SARS-CoV-2 on post-mortem lung samples of positive deceased subjects. A total of 27 samples were analyzed by RT-PCR targeting different viral RNA sequences of SARS-CoV-2, including envelope (E), nucleocapsid (N), spike (S), and open reading frame (ORF1ab) genes and ISH targeting S and Orf1ab. All 27 cases showed the N gene amplification, 22 out of 27 the E gene amplification, 26 out of 27 the S gene amplification, and only 6 the ORF1ab gene amplification. The S ISH was positive only in 12 out of 26 cases positive by RT-PCR. The S ISH positive cases with strong and diffuse staining showed a correlation with low values of the number of the amplification cycles by S RT-PCR suggesting that ISH is a sensitive assay mainly in cases carrying high levels of S RNA. In conclusion, our findings demonstrated that ISH assay has lower sensitivity to detect SARS-CoV-2 in FFPE compared to RT-PCR; however, it is able to localize the virus in the cellular context since it preserves the morphology.

Unsuspected Xp11 Translocation Renal Neoplasm Associated With Contralateral Clear Cell Carcinoma.

In this report, we present for the first time the coexistence of a conventional renal cell carcinoma (RCC) and an undefined Xp11 translocation renal neoplasm in distinct kidneys, which was difficult to definitively classify as either carcinoma or PEComa (perivascular epithelioid cell tumor). While one of the tumors showed the morphological and immunohistochemical features of clear RCC, the other had an unusual morphology with a prominent nested pattern. Microscopically this tumor showed nests of cells with clear and eosinophilic cytoplasm and nuclei with prominent nucleoli; some hyaline globules were evident. Immunohistochemical panel showed negativity for cytokeratin-pan, cytokeratin-7, PAX8, and CD10 but positive immunostaining for cathepsin K, racemase, Melan-A, and TFE3. A subsequent, metaphase, dual-color fluorescence in situ hybridization confirmed the Xp11 translocation. Attention should be paid to the routine immunohistochemical profile that, in case of negativity of specific RCC markers, may suggest an Xp11 translocation renal tumor. The addition of TFE3 can easily identify the specific subtype.

Clinical activity and tolerability of FOLFIRI and cetuximab in elderly patients with metastatic colorectal cancer in the CAPRI-GOIM first-line trial.

BACKGROUND: In the cetuximab after progression in KRAS wild-type colorectal cancer patients (CAPRI) trial patients with metastatic colorectal cancer (mCRC) received 5-fluorouracil, folinic acid and irinotecan (FOLFIRI) and cetuximab in first line followed by 5-Fluorouracil, folinic acid, oxaliplatin (FOLFOX) with or without cetuximab until progression. Limited data are available on the efficacy and safety of anti-epidermal growth factor receptor (anti-EGFR) agents on elderly patients with mCRC. In the current study we evaluated the efficacy and safety of FOLFIRI plus cetuximab in age-defined subgroups. METHODS: A post-hoc analysis was performed in CAPRI trial patients; outcomes (progression-free survival (PFS), overall response rate (ORR), safety) were analysed by age-groups and stratified according to molecular characterisation. 3 age cut-offs were used to define the elderly population (≥65; ≥70 and ≥75 years). RESULTS: 340 patients with mCRC were treated in first line with FOLFIRI plus cetuximab. Among those, 154 patients were >65 years, 86 >70 years and 35 >75 years. Next-generation sequencing (NGS) was performed in 182 patients. Among them, 87 patients were >65 years, 46 >70 and 17 >75. 104 of 182 patients were wild type (WT) for KRAS, NRAS, BRAF, PIK3CA genes. In the quadruple WT group, 51 patients were ≥65 years; 29 were ≥70; 9 were ≥75. Median PFS was similar within the age-subgroups in the intention-to-treat population, NGS cohort and quadruple WT patients, respectively. Likewise, ORR was not significantly different among age-subgroups in the 3 populations. Safety profile was acceptable and similarly reported among all age-groups, with the exception of grade ≥3 diarrhoea (55% vs 25%, p=0.04) and neutropaenia (75% vs 37%, p=0.03) in patients ≥75 years and grade ≥3 fatigue (31% vs 20%, p=0.01) in patients <75 years. CONCLUSIONS: Tolerability of cetuximab plus FOLFIRI was acceptable in elderly patients. Similar ORR and PFS were observed according to age-groups. No differences in adverse events were reported among the defined subgroups with the exception of higher incidence of grade ≥3 diarrhoea and neutropaenia in patients ≥75 years and grade ≥3 fatigue in patients <75 years. TRIAL REGISTRATION NUMBER: 2009-014041-81.

Sanger sequencing in routine KRAS testing: a review of 1720 cases from a pathologist's perspective.

BACKGROUND: Sanger sequencing (SS) of PCR products is still the most frequent method to test colorectal cancer for KRAS mutations in routine practice. METHODS: An audit of SS on 1720 routine cases was carried out, taking into account age, gender, specimen type (resection vs biopsies), tumour site (primary vs metastasis), tumour stage, neoplastic cells abundance (>30% vs <30%) and fixation type (buffered formalin vs simple formalin). In a subset of 50 wild-type (WT) patients correlations between SS findings and response rate (RR), progression-free survival (PFS) and overall survival (OS) were also evaluated. RESULTS: The tests were informative in 1691 cases (98.3%). Mutations were detected in 671 cases (39.6%). No significant differences in mutation rates were observed with respect to age (p=0.2), gender (p=0.2), specimen type (p=0.3) and formalin fixation (p=0.08). Conversely, KRAS mutant rate was higher in metastatic tissue (50% vs 39%, p=0.02), in samples with over 30% of neoplastic cells (43.4% vs 26.6%, p=0.02) and in tumours tested in stage IV (p=0.05). The RR of SS KRAS WT patients was 26% (one complete and 12 partial responses). The disease control rate (objective responses plus stable disease) was 56%. Median PFS was 4.4 months and median OS was 10.4 months. CONCLUSIONS: Pathological criteria that make SS a more robust method for KRAS testing and treatment response prediction are neoplastic cell abundance, metastatic tissue sample and stage IV primary tumour.

BRAF/NRAS mutation frequencies among primary tumors and metastases in patients with melanoma.

PURPOSE: The prevalence of BRAF, NRAS, and p16CDKN2A mutations during melanoma progression remains inconclusive. We investigated the prevalence and distribution of mutations in these genes in different melanoma tissues. PATIENTS AND METHODS: In all, 291 tumor tissues from 132 patients with melanoma were screened. Paired samples of primary melanomas (n = 102) and synchronous or asynchronous metastases from the same patients (n = 165) were included. Tissue samples underwent mutation analysis (automated DNA sequencing). Secondary lesions included lymph nodes (n = 84), and skin (n = 36), visceral (n = 25), and brain (n = 44) sites. RESULTS: BRAF/NRAS mutations were identified in 58% of primary melanomas (43% BRAF; 15% NRAS); 62% in lymph nodes, 61% subcutaneous, 56% visceral, and 70% in brain sites. Mutations were observed in 63% of metastases (48% BRAF; 15% NRAS), a nonsignificant increase in mutation frequency after progression from primary melanoma. Of the paired samples, lymph nodes (93% consistency) and visceral metastases (96% consistency) presented a highly similar distribution of BRAF/NRAS mutations versus primary melanomas, with a significantly less consistent pattern in brain (80%) and skin metastases (75%). This suggests that independent subclones are generated in some patients. p16CDKN2A mutations were identified in 7% and 14% of primary melanomas and metastases, with a low consistency (31%) between secondary and primary tumor samples. CONCLUSION: In the era of targeted therapies, assessment of the spectrum and distribution of alterations in molecular targets among patients with melanoma is needed. Our findings about the prevalence of BRAF/NRAS/p16CDKN2A mutations in paired tumor lesions from patients with melanoma may be useful in the management of this disease.

EGFR mutations detection on liquid-based cytology: is microscopy still necessary?

Currently, there is a trend towards an increasing use of liquid-based cytology (LBC) to diagnose non-small cell lung cancer. In this study, to detect epidermal growth factor receptor mutations, different molecular techniques were applied to LBC samples with and without laser capture microdissection (LCM). In 58 LBCs, DNA was extracted twice. One sample was obtained directly from CytoLyt solution, whereas the other DNA sample was derived after slide preparation and LCM of Papanicolaou-stained cells. The rate of mutant cases obtained by direct sequencing was discordant between CytoLyt-derived (10.3%) and LCM-derived (17.2%) DNA. However, the same mutant rate (17.2%) was achieved on the matched samples by high-resolution melting analysis, fragment and TaqMan assays. Thus, LCM and direct sequencing may be replaced by more sensitive non-sequencing methods directly performed on CytoLyt-derived DNA, an easier and faster approach to improve epidermal growth factor receptor testing standardisation on LBCs.

EGFR and KRAS mutations detection on lung cancer liquid-based cytology: a pilot study.

In advanced non-small-cell lung carcinomas epidermal growth factor receptor (EGFR) and KRAS testing is often performed on cytology. Liquid-based cytology (LBC), which eliminates the need for slide preparation by clinicians, may be very useful. In 42 LBC DNA was extracted twice. One sample was obtained directly from CytoLyt solution, whereas the other DNA sample was derived after smear preparation and laser capture microdissection (LCM) of Papanicolaou-stained cells. EGFR and KRAS mutational analyses were performed by direct sequencing. On CytoLyt-derived DNA four EGFR (9%) and five KRAS (12%) gene mutations were found. When direct sequencing was performed after LCM, the rate of cases that displayed either EGFR or KRAS mutations increased from 21% to 40%. Although time-consuming, LCM makes direct sequencing highly sensitive even on LBC preparations containing only a few cells.

Lymph node-based disease and HHV-8/KSHV infection in HIV seronegative patients: report of three new cases of a heterogeneous group of diseases.

We describe three cases of lymph proliferative diseases characterized by the presence of lymphoma cells expressing the KSHV/HHV-8 antigen with or without EBV expression. The patients were HIV seronegative without serous effusions. One case was diagnosed as KSHV-germinotropic lymphoproliferative disorder due to the presence of atypical plasmablasts involving germinal centers. These plasmablasts were positive for MUM1 and vIL6, co-expressed EBV and LNA-1 of HHV-8/KSHV, and showed a polyclonal pattern of Ig gene rearrangements on PCR. The disease was localized and the prognosis was good. In two other cases, a diagnosis of KSHV/HHV-8-related diffuse large cell B-lymphoma morphology was made. The lymphoma cells were anaplastic or frankly pleomorphic, expressed KSHV but not EBV, and were positive for CD20, MUM1, PAX-5, and vIL6. In both cases the prognosis was poor. On the basis of the features observed, we raise three considerations: (1) KSHV-related lymphoproliferative disorders represent a distinctive and heterogeneous group of diseases with variable clinico-pathologic findings and immunophenotypes (BCL6-/MUM1+/CD138- and BCL6+/MUM1+/CD138- or BCL6-/MUM1+/CD138+). (2) Although the pathogenic mechanism of HHV8 in lymphomagenesis is unclear, the presence the viral DNA in lymph nodes of HIV- patients is not a simply opportunistic infection, but is directly implicated in the pathogenesis of KSHV-related diseases; the activation of IL-6 receptor signalling may play an important role in most cases. (3) The different prognoses among different diseases with KSHV etiology may be related to the fact that the pathogenic potential appears to be constrained by a competent immune system.

KRAS mutations testing in colorectal carcinoma patients in Italy: from guidelines to external quality assessment.

BACKGROUND: Monoclonal antibodies directed against the epidermal growth factor receptor (EGFR) have been approved for the treatment of patients with metastatic colorectal carcinoma (mCRC) that do not carry KRAS mutations. Therefore, KRAS testing has become mandatory to chose the most appropriate therapy for these patients. METHODOLOGY/PRINCIPAL FINDINGS: In order to guarantee the possibility for mCRC patients to receive an high quality KRAS testing in every Italian region, the Italian Association of Medical Oncology (AIOM) and the Italian Society of Pathology and Cytopathology -Italian division of the International Academy of Pathology (SIAPEC-IAP) started a program to improve KRAS testing. AIOM and SIAPEC identified a large panel of Italian medical oncologists, pathologists and molecular biologists that outlined guidelines for KRAS testing in mCRC patients. These guidelines include specific information on the target patient population, the biological material for molecular analysis, the extraction of DNA, and the methods for the mutational analysis that are summarized in this paper. Following the publication of the guidelines, the scientific societies started an external quality assessment scheme for KRAS testing. Five CRC specimens with known KRAS mutation status were sent to the 59 centers that participated to the program. The samples were validated by three referral laboratories. The participating laboratories were allowed to use their own preferred method for DNA extraction and mutational analysis and were asked to report the results within 4 weeks. The limit to pass the quality assessment was set at 100% of true responses. In the first round, only two centers did not pass (3%). The two centers were offered to participate to a second round and both centers failed again to pass. CONCLUSIONS: The results of this first Italian quality assessment for KRAS testing suggest that KRAS mutational analysis is performed with good quality in the majority of Italian centers.

Detection of KRAS mutations in colorectal carcinoma patients with an integrated PCR/sequencing and real-time PCR approach.

AIMS: Patients with metastatic colorectal carcinoma (mCRC) carrying activating mutations of the KRAS gene do not benefit from treatment with anti-EGF receptor monoclonal antibodies. Therefore, KRAS mutation testing of mCRC patients is mandatory in the clinical setting to aid in the choice of appropriate therapy. MATERIALS & METHODS: We developed a cost-effective approach for the determination of KRAS mutations in codons 12 and 13 in clinical practice based on a sensitive PCR/sequencing technique and the commercially available real-time PCR-based Therascreen kit (DxS Ltd). RESULTS & CONCLUSION: The PCR/sequencing test was able to detect 10% mutant DNA in a background of wild-type DNA. By using this assay, we determined the mutational status of KRAS in 527 out of 540 (97.6%) formalin-fixed paraffin-embedded tissues from mCRC patients. PCR/sequencing was not conclusive in 13 cases, in which low-intensity peaks suggestive of potential mutations were identified. The DxS assay, which showed a sensitivity of 1%, identified mutations in 11 out of 13 inconclusive cases. Interestingly, five of these 11 cases showed high levels of DNA fragmentation. No significant difference was found in the ability of PCR/sequencing and DxS to identify KRAS mutations within 160 cases with more than 30% tumor cells. However, in 24 samples with less than 30% tumor cells, DxS showed an higher sensitivity. In conclusion, our findings suggest that PCR/sequencing can be used for mutational analysis of the majority of tumor samples that have more than 30% tumor cell content, whereas more sensitive and expensive tests should be reserved for inconclusive cases and for samples with a low amount of tumor cells.

Review article: pulmonary sarcomatoid carcinomas: a practical overview.

Pulmonary sarcomatoid carcinomas (PSCs) are currently defined as poorly differentiated non-small-cell carcinomas containing a component with sarcoma or sarcoma-like (spindle and/or giant cell) features. They consist of 5 major histological variants, namely pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. The segregation of PSCs into a distinct clinicopathologic entity seems justified on the basis of morphologic, behavioral, and genotypic/phenotypic attributes. As a group, PSCs generally run an aggressive clinical course and may cause major difficulties in the differential diagnosis with other primary and secondary malignancies of the lung. At present, PSCs are believed to represent a family of carcinomas "in transition," in which diverse pathways of clonal evolution account for histological differences of a common ancestor lesion. The sarcomatous or sarcomatoid component of these tumors is thought to derive from carcinoma cells during the progression of carcinogenesis through the activation of an epithelial-mesenchymal transition program leading to sarcomatous transformation or metaplasia (conversion paradigm). Conceivably, targeting the epithelial-mesenchymal transition program could become a valid therapeutic strategy for these life-threatening tumors, whose sensitivity to current medical manipulation is disappointing.

A minute focus of extranodal marginal zone B-cell lymphoma arising in Hashimoto thyroiditis diagnosed with PCR after laser capture microdissection: a case report.

BACKGROUND: Primary thyroid gland lymphomas are uncommon tumours that occur in the setting of lymphocytic thyroiditis or Hashimoto's disease in almost all cases. In this condition a distinction between an inflammatory lymphoid infiltrate and a low grade lymphoma may be extremely difficult and precise criteria are necessary for a correct diagnosis. PATIENT AND METHODS: We report a case of a minute focus of primary extranodal marginal zone B-cell lymphoma (EMZBCL), incidentally discovered in a 63-year-old man with Hashimoto thyroiditis (HT) and diagnosed by means of polymerase chain reaction (PCR) after laser capture microdissection.The histological examination of surgical specimen confirmed the diagnosis of HT and showed a minute focus of dense lymphoid infiltrate (less than 4 mm in diameter), composed by centrocyte-like cells forming MALT balls. Immunoistochemistry was not useful. A microscopic focus of EMZBCL was suspected on the basis of morphological features. PCR assays revealed the rearrangement of the heavy chain of immunoglobulins only in the microdissected suspicious area, confirming the diagnosis of EMZBCL. CONCLUSION: Our finding suggests that in cases of autoimmune thyroiditis a careful examination of the thyroid specimen is warranted, in order to disclose areas or small foci of lymphomatous transformation. Furthermore, in difficult cases with doubtful immunohistological findings, ancillary techniques, such as molecular studies, are necessary for a conclusive diagnosis.

Clear cell "sugar" tumors of urethra: a previously undescribed occurrence and review of published data.

Clear cell "sugar" tumor is a rare benign tumor considered as a member of the family of perivascular epithelioid cell tumors. To the best of our knowledge, this is the first case of clear cell "sugar" tumor presented as a mass protruding from the urethra in a 15-year-old girl. Pathologic examination revealed a tumor composed of epithelioid cells with "water" clear cytoplasm that stained positively for melanocytic and smooth muscle-specific markers. Treatment of this tumor included a surgical excision and complete removal of the urethral mass, with examination of surgical margins. Three months after surgery, the patient remains clinically free of disease.

The influence of clinical information in the histopathologic diagnosis of melanocytic skin neoplasms.

BACKGROUND: We tested the relevance of clinical information in the histopathologic evaluation of melanocytic skin neoplasm (MSN). METHODS: Histopathologic specimens from 99 clinically atypical MSN were circulated among ten histopathologists; each case had clinical information available in a database with a five-step procedure (no information; age/sex/location; clinical diagnosis; clinical image; dermoscopic image); each step had a histopathologic diagnosis (D1 through D5); each diagnostic step had a level of diagnostic confidence (LDC) ranging from 1 (no diagnostic certainty) to 5 (absolute diagnostic certainty). The comparison of the LDC was employed with an analysis of variance (ANOVA) for repeated measures. FINDINGS: In D1 (no information), 36/99 cases (36.3%) had unanimous diagnosis; in D5 (full information available), 51/99 cases (51.5%) had unanimous diagnosis (p for difference between proportions <0.001). The observer agreement expressed as kappa increased significantly from D1 to D5. The mean LDC linearly increased for each observer from D1 through D5 (p for linear trend <0.001). On average, each histopathologist changed his initial diagnosis in 7 cases (range: 2-23). Most diagnostic changes were in D2 (age/sex/location). INTERPRETATION: The histopathologic criteria for the diagnosis of MSN can work as such, but the final histopathologic diagnosis is a clinically-aided interpretation. Clinical data sometimes reverse the initial histopathologic evaluation.

Detection of mucosal and cutaneous human papillomaviruses in oesophagitis, squamous cell carcinoma and adenocarcinoma of the oesophagus.

BACKGROUND: Epidemiologic evidence points to a connection between viral infections by the human papillomavirus (HPV) and a subgroup of squamous cell carcinomas of the oropharynx. Still controversial is the association of HPV infection with oesophageal neoplasia. OBJECTIVES: To investigate the presence of mucosal as well as cutaneous HPVs in squamous cell carcinoma and adenocarcinoma of the oesophagus. STUDY DESIGN: HPV DNA has been searched by PCR and characterized by nucleotide sequence analysis in paraffin-embedded biopsies from Italian patients with oesophageal squamous cell carcinoma (n=36), sarcomatoid cell carcinoma (n=1), adenocarcinoma (n=20) and oesophagitis lesions (n=27). RESULTS: A broad spectrum of HPVs, primarily cutaneous types was demonstrated in 27.8% (10/36) of squamous cell carcinomas with a significantly higher frequency in well (G1) and moderately (G2) differentiated grades (47.3%, 9/19) compared to poorly (G3) differentiated (5.9%, 1/17) squamous cell carcinoma (p=0.008), and in 10% (2/20) of adenocarcinomas and in 29.6% (8/27) of oesophagitis. HPV types detected included mucosal types HPV 6 and 16, cutaneous types HPV 8, 15, 20 and 25; and the putative new HPV types X14, X15, DL473, PPHL1FR and CJ198. CONCLUSIONS: There is no evidence of any association between mucosal HPVs and oesophageal neoplasia. The cutaneous HPVs are detected at low frequency in adenocarcinoma and poorly differentiated squamous cell carcinoma, while they are frequently detected in oesophagitis and in well and moderately differentiated squamous cell carcinoma suggesting their tropism for keratinized tissue, although a significant association with such neoplasias cannot be drawn.

Nonpolypoid intestinal mantle cell lymphoma resembling MALT lymphoma with successful response to rituximab.

Two unusual cases of mantle cell lymphoma are reported. They involved the ileum and right colon without multiple lymphomatous polyposis and morphologically resembled an extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type.

Fluorescent in situ hybridization as a screening test for HER2 amplification in G2 and G3 breast cancers of lobular and ductal histotype and metastases.

The aim of the present study was to evaluate the effectiveness of fluorescence in situ hybridisation (FISH), as a screening test, in moderately- (G2) or poorly- (G3) differentiated breast cancers of the ductal (IDC) and lobular (ILC) histotypes and distant metastases. HER2 FISH was performed on 486 G2 and 477 G3 both of IDC and ILC histotypes and in 241 metastases. A significant difference in the HER2 amplification was observed between G2 (14.8%) and G3 (31.9%), with no difference according to the histotype. However, the rate of amplification increased to 36% in the G2/hormone receptor-negative cases as compared to 10.6% in the G2/receptor-positive cases (p<0.0001). HER2 was amplified in 17% of metastases with some differences depending on the location. These data suggest that the HER2 FISH analysis may be an effective screening test in breast cancer metastases and G3 tumors, irrespective of the hormone receptor status or presence of lymphovascular invasion.