Stefan Steurer

Introduction: Myxovirus resistance protein 1 (MX1) contributes to resistance against viral infections, including to influenza, and has recently been implicated in cancer. Methods: A tissue microarray with 17,909 samples from 145 tumor types/subtypes and 608 samples from 76 normal tissue types was analyzed by immunohistochemistry (IHC) to assess MX1 expression. Results: MX1 positivity was found in tumor cells of 5956 of 14,512 analyzable samples, and 131 of 145 entities included at least one positive case. High positivity rates occurred in squamous cell carcinomas (up to 88%), neuroendocrine neoplasms (up to 85%), germ cell neoplasms (up to 77%), salivary gland tumors (up to 75%), mesothelioma (up to 74%), endometrial and ovarian carcinomas (up to 73%), cervical adenocarcinoma (73%), pancreatic ductal adenocarcinoma (65%), and urothelial carcinoma (up to 62%). MX1 expression correlated with PD-L1 positivity and CD8+ lymphocyte density (p < 0.0001 each). High MX1 expression was linked to grade progression in breast cancer (p < 0.0001), microsatellite instability in colorectal adenocarcinoma (p = 0.0003), high grade (p = 0.0431) and advanced pT stage (p = 0.0269) in hepatocellular carcinoma, distant metastasis in clear cell renal cell carcinoma (ccRCC, p = 0.0164), and nodal metastasis in papillary RCC (pRCC; p = 0.0326). Low MX1 expression was linked to stage progression in muscle-invasive urothelial carcinoma (p = 0.0372) and colorectal adenocarcinoma (p = 0.0002), papillary (p = 0.013) and follicular (p = 0.0221) thyroid cancer, and nodal metastasis in serous high-grade ovarian carcinoma (p = 0.0355). MX1 expression was unrelated to phenotype in endometrioid endometrial and ovarian carcinoma. Conclusions: MX1 expression in tumors is strongly linked to CD8+ lymphocyte density and PD-L1 expression, suggesting an association with an immune-inflamed, type I interferon-related tumor microenvironment.

Background/Objectives: Annexin A4 (ANXA4) is one of twelve members of the annexin superfamily that bind membrane phospholipids in a calcium-dependent manner, and which are involved in several processes related to the membrane. Methods: To learn more about the role of ANXA4 in cancer, the ANXA4 expression was analyzed by immunohistochemistry (IHC) on tissue microarrays (TMAs) containing 17,654 tumors and precursor lesions from 148 tumor types. Results: ANXA4 immunostaining was found in 10,858 (83.4%) of 13,017 analyzable tumors, and was considered weak in 10.1%, moderate in 16.6%, and strong in 61.8% of cases. Of 148 tumor categories, 144 showed ANXA4 staining in at least one case and 133 included at least one case with strong staining. Among tumor entities with at least 10 evaluable samples, strong ANXA4 staining in >50.0% of cases was seen in 56 of 120 entities, while absence of staining in >50.0% of cases was seen in 13. Clinically important tumor entities where ANXA4 staining was always positive (>99.5%) included gallbladder adenocarcinoma, cholangiocarcinoma, pancreatic/ampullary, various subtypes of salivary gland tumors, papillary renal cell carcinoma, urothelial carcinoma, squamous and basal cell carcinoma of the skin, and epithelioid mesothelioma. A reduced ANXA4 expression was linked to features of cancer aggressiveness in breast cancer, clear cell renal cell carcinoma, urothelial carcinoma, pancreatic ductal adenocarcinoma, hepatocellular carcinoma, colorectal adenocarcinoma, and follicular thyroid carcinoma. Conclusions: It is concluded that ANXA4 is abundantly expressed in human malignancies and that a reduced expression may be linked to unfavorable disease characteristics in many important tumor entities.

Background: TROP2 (TACSTD2) is a therapeutic target of antibody–drug conjugates and is broadly expressed in epithelial malignancies. Data on TROP2 protein expression in large, clinically annotated prostate cancer cohorts, particularly in recurrent disease, remain limited. Methods: TROP2 immunohistochemistry was performed on a prostate cancer tissue microarray comprising 17,747 primary radical prostatectomy specimens and 258 recurrent prostate cancer samples. TROP2 staining data were compared with clinicopathological parameters, biochemical recurrence and ERG status. Results: Among 12,807 interpretable primary prostate cancers, TROP2 staining was detectable in all cases and considered strong in 94.5%, moderate in 3.5%, and weak in 2.0%. Reduced TROP2 was statistically associated with high pT stage (p = 0.0011) and high Gleason grade (p < 0.0001), but absolute differences were small. Reduced TROP2 expression levels were unrelated to PSA recurrence in the entire cohort (p = 0.0787) but statistically linked to early PSA recurrence in ERG positive cancers (p = 0.0165). In four different scenarios of multivariate analyses, reduced TROP2 expression did not show an unequivocal independent prognostic role. As compared to primary tumors, TROP2 was markedly reduced among 250 evaluable recurrent cancers (strong 57.6%, moderate 31.6%, weak 8.4%, negative 2.4%; p < 0.0001 vs. primary cancers). Reduced TROP2 was also significantly more frequent in recurrent cancers than in the subgroup of high-grade primary tumors (Gleason ≥ 4+4; strong 57.6% vs. 90.2%; p < 0.0001). Conclusions: TROP2 is consistently expressed at high levels in primary prostate cancer but often reduced in recurrent disease. While uniform expression in primary tumors supports TROP2 as a therapeutic target in prostate cancer, reduced expression in many recurrent cancers highlights the potential need for TROP2 expression measurement as a predictive test in this subgroup.

Background/Objectives: Thymidylate synthase (TYMS) represents an important therapeutic target. Methods: In this study, TYMS expression was analyzed by immunohistochemistry on a tissue microarray containing 17,371 samples from 136 different tumor types. Results: TYMS staining was seen in 42.9% of 15,361 analyzable tumors, with weak staining in 35.4%, moderate in 5.7%, and strong in 1.8%. TYMS occurred in at least one case of 127 categories, of which 71 showed TYMS staining in at least 50% of cases, and 56 included at least one case with strong positivity. TYMS positivity occurred most commonly in lymphomas (81.3–96.5%), sarcomas and sarcomatoid carcinomas (33.3–100%), malignant melanoma (70.5–90.7%), cervical adenocarcinoma (78.3%), and squamous cell carcinomas of various sites (57.1–77.9%). High TYMS expression was linked to advanced pT (p = 0.0097), high grade (p < 0.0001), ER negativity (p < 0.0001), and PR negativity (p = 0.0002) in invasive breast cancer of no special type; high grade (p < 0.0050), high UICC stage (p = 0.0060), and nodal metastasis (p = 0.0120) in clear cell renal cell carcinoma (RCC); high grade (p < 0.05) and nodal metastasis (p = 0.0045) in papillary RCC; high Gleason grade (p < 0.0001) and advanced pT stage (p = 0.0149) in prostatic adenocarcinoma; high pT (p < 0.0001), nodal metastasis (p = 0.005), lymphatic (p = 0.0064) and venous invasion (p = 0.0005), left side location (p < 0.0001), and microsatellite instability (p < 0.0001) in colorectal adenocarcinoma; and high grade (p < 0.0001) in squamous cell carcinomas of different sites. Conclusions: TYMS is often overexpressed across different cancer entities and shows associations with several adverse histopathological parameters commonly used to describe tumor phenotypes.

Background/Objectives: The double-strand break repair protein MRE11 forms the core of the MRE11/RAD50/NBS1 (MRN) complex. Cancers with reduced MRE11 expression have been suggested to be more sensitive to radio-chemotherapy and may be subject to synthetic lethality. The aim of this study was to assess the prevalence of MRE11 deficiency and the potential role and clinical significance of elevated and/or reduced MRE11 expression in human cancer. Methods: A tissue microarray containing 14,966 samples from 134 different tumor entities was analyzed for MRE11 by immunohistochemistry. Results: In normal tissues, strong nuclear MRE11 staining occurred in almost all cell types. In cancers, nuclear MRE11 staining was strong in 11,797 (91.0%), moderate in 1018 (7.9%), weak in 86 (0.7%), and completely absent (MRE11 deficiency) in 55 (0.4%) of 12,956 informative tumor samples. Only six tumor entities had more than one MRE11-deficient cases including hepatocellular carcinoma (9 of 193), intestinal type gastric adenocarcinoma (4 of 208), endometrioid endometrial carcinoma (5 of 268), pulmonary adenocarcinoma (2 of 165), colorectal adenocarcinoma (CRC, 16 of 2183), and clear cell renal cell carcinoma (ccRCC, 7 of 1011). Reduced MRE11 staining was associated with mismatch repair deficiency (dMMR) in CRC and in gastric adenocarcinoma (p < 0.0001 each), advanced pT stage (p = 0.0003) and L1 status (p = 0.0019) in testicular seminoma, high grade (p < 0.05), advanced pT (p < 0.0001), and high UICC stage (p = 0.0014) in ccRCC, advanced pT stage in high-grade serous ovarian carcinoma (p = 0.0396), and nodal metastases in papillary thyroid cancer (p = 0.0332). Conclusions: MRE11 is highly expressed in most cancers. Reduced MRE11 expression is associated with aggressive phenotype in multiple cancer types. The potential to exploit MRE11 deficiency as a target for synthetic lethality deserves to be further explored.

Background/Objectives: Aberrant expression of high-mobility group protein B1 (HMGB1) has been linked to cancer development and progression. Methods: To better comprehend the role of HMGB1 expression in cancer, a tissue microarray containing 14,966 samples from 134 different tumor entities and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. Results: Strong HMGB1 staining occurred in almost all normal cell types and in most cancers. Of 11,808 evaluable cancers, only 7.8% showed complete absence of HMGB1 staining (HMGB1 deficiency) while 9.9% showed 1+, 25.0% showed 2+, and 57.2% showed 3+ HMGB1 positivity. Absence of HMGB1 staining mostly occurred in pheochromocytoma (90.0%), seminoma (72.4%), gastrointestinal stromal tumor (28.6%), adrenal cortical carcinoma (25.0%), and Hodgkin’s lymphoma (25.0%). Low HMGB1 staining was linked to poor histologic grade (p < 0.0001), advanced pT stage (p < 0.0001), high UICC stage (p < 0.0001), and distant metastasis (p = 0.0413) in clear cell renal cell carcinoma, invasive tumor growth in urothelial carcinoma (pTa vs. pT2–4, p < 0.0001), mismatch repair deficiency (p = 0.0167) in colorectal cancers, and advanced pT stage in invasive breast carcinoma of no special type (p = 0.0038). Strong HMGB1 staining was linked to nodal metastases in high-grade serous ovarian carcinomas (p = 0.0213) and colorectal adenocarcinomas (p = 0.0137), as well as to poor histological grade in squamous cell carcinomas (p = 0.0010). Conclusions: HMGB1 deficiency and reduced HMGB1 expression occur in a broad range of different tumor entities. Low rather than strong HMGB1 staining is often linked to an aggressive tumor phenotype. Whether HMGB1 deficiency renders cells susceptible to specific drugs remains to be determined.

Background: The glucocorticoid receptor (GR) regulates the transcription of thousands of genes. In cancer, both oncogenic and tumor suppressive roles of GR have been proposed. Methods: A tissue microarray containing 18,527 samples from 147 tumor (sub-)types and 608 samples from 76 normal tissue types was analyzed for GR expression by immunohistochemistry. Results: GR positivity was found in 76.4% of 14,349 interpretable cancers, including 18.5% with weak, 19.6% with moderate, and 38.3% with strong positivity. GR positivity appeared in all 147 tumor types, with at least one strongly positive tumor in 136 types. Of out tumor entities, 77 of the 147 showed GR positivity in 100% of the cases analyzed. Only six tumor types had less than 50% GR-positive cases, including adenomas with low-/high-grade dysplasia (32.5%/21.7%), adenocarcinomas (17%) and neuroendocrine carcinomas (45.5%) of the colorectum, endometrial carcinomas (25.6%), and rhabdoid tumors (25%). Reduced GR staining was associated with grade progression in pTa (p < 0.0001) and with nodal metastasis in pT2-4 (p = 0.0051) urothelial bladder carcinoma, advanced pT stage (p = 0.0006) in breast carcinomas of no special type (NST), and high grade (p = 0.0066), advanced pT stage (p < 0.0001), and distant metastasis (p = 0.0081) in clear cell renal cell carcinoma. GR expression was unrelated to clinico-pathological parameters in gastric, pancreatic, and colorectal adenocarcinoma, and in serous high-grade carcinoma of the ovary. Conclusions: GR expression is frequent across all cancer types. Associations between reduced GR expression and unfavorable tumor features in certain cancers suggest that the functional importance of GR-regulated genes in cancer progression depends on the cell of tumor origin.

Background: The complete loss of S-methyl-5′-thioadenosine phosphorylase (MTAP) expression, often due to homozygous 9p21 deletion, creates a druggable vulnerability in cancer cells. Methods: A total of 769 primary pancreatic ductal adenocarcinomas were analyzed on tissue microarrays with MTAP immunohistochemistry (IHC) and 9p21 fluorescence in situ hybridization (FISH). Intratumoral heterogeneity was assessed on a “heterogeneity” TMA containing up to nine samples from different areas of 236 primary tumor and nodal metastases, and whole sections of all tumor blocks from 19 cancers. Results: MTAP expression loss was found in 181 (37.9%) of 478 interpretable primary tumors and was unrelated to pT, pN, grade, and tumor size. MTAP expression loss was homogenous in 37.6% and heterogeneous in 1.1% of the 181 tumors, with at least three evaluable samples on the heterogeneity TMA. On whole sections, 1 of 19 tumors showed heterogeneous MTAP loss. The correlation between IHC and FISH was nearly perfect, with 98.8% of MTAP-deficient samples showing a 9p21 deletion. Conclusions: MTAP expression loss is frequent, caused by homozygous deletion, and mostly homogeneous in pancreatic ductal adenocarcinomas. Considering also their aggressive clinical behavior, pancreatic adenocarcinomas may represent an ideal cancer type for studying new drugs targeting MTAP-deficient cancer cells in clinical trials.

Background: Major diagnostic and therapeutic changes led to the implementation of the ‘lung cancer diagnosis in small biopsies and cytology specimens’ concept in the WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart in 2015. Touch imprints are an established technique in cytology that provides a rapid and minimally invasive method for morphological diagnoses of clinical specimens, accurate subtyping, and molecular characterizations of malignancies. The extended diagnostic requirements from the increasingly limited material provided by minimally invasive biopsy techniques pose major challenges for pathology. Recognizing the relevant features and potential pitfalls is essential for cytologists to avoid misinterpretation. Materials and Methods: A retrospective analysis of endoscopic and surgical biopsy diagnostics was performed on 717 patients (303 women and 414 men; average age of 66.9 years) with clinically suspicious tumor findings at the LungenClinic Grosshansdorf in 2020. A total of 1363 cytological samples were obtained pre-therapeutically from 986 distinct biopsies covering 330 surgically and 656 endoscopically examined pulmonary, mediastinal, and bronchial regions. These samples were then compared with the histological diagnoses that were critical for determining the final therapy. Results: Out of a total of 656 endoscopically examined cases, 322 were classified as malignant, 308 as benign, and 26 as undetermined. While touch imprints and histological analysis separately achieved specificity values of 95.4% and 98.8%, both methods showed sensitivity values of 82.1% and 86.5%, respectively. In contrast, combining the two methods improved the sensitivity by 8 percentage points to 94.6%. Out of 330 cases of surgically examined samples, 137 were malignant, 190 were benign, and 3 were undetermined. The specificity of the morphological examinations for these samples was comparably high at 97.9% and 100%, respectively. In this surgical setting, touch imprints alone achieved a sensitivity of 75.9% (n = 104/137 cases), with a specificity of 97.9% (n = 186/190 cases). The outcome of the histological approach alone and in combination with touch imprints reached a sensitivity of 96.4% (n = 132/137 cases). Conclusions: Cytology and histology achieved comparably high sensitivity and specificity values on small biopsies. Under optimal conditions for morphological analysis in a surgical setting, the sensitivity of cytology for detecting malignant tumors was only 6 percentage points lower compared with the clinical endoscopic setting. A combined approach of cytologic–histologic evaluation for endoscopically examined specimens significantly increased the sensitivity by approximately 8% compared with the surgical setting (p < 0.003).

Background/Objectives: Carcinoembryonic antigen (CEA) is a cell-surface glycoprotein serving as a drug target, diagnostic marker, and serum marker for cancer monitoring. However, prevalence data on CEA expression in cancer tissues vary considerably. This study was designed to determine CEA expression in normal and neoplastic tissues. Methods: A tissue microarray containing 13,725 samples from 120 different tumor types, as well as 76 different normal tissue types, was analyzed by immunohistochemistry (IHC). Results: CEA was detectable in 65 (54.2%) of 120 tumor categories, including 49 (40.8%) tumor types with at least one strongly positive case. CEA positivity was most common in colorectal adenomas (100%) and carcinomas (98.7%), other gastrointestinal adenocarcinomas (61.1–80.3%), medullary carcinomas of the thyroid (96.3%), pulmonary adenocarcinoma (73.7%), mucinous carcinomas of the ovary (79.8%) and the breast (43.2%), small-cell carcinomas of the lung (64.3%), and urinary bladder (38.9%). CEA overexpression was linked to high tumor grade and invasive growth (p < 0.0001 each) in urinary bladder cancer, and estrogen and HER2 receptor positivity (p ≤ 0.0158) in invasive breast cancer of no special type. In colorectal adenocarcinomas, reduced CEA expression was associated with mismatch repair deficiency (p < 0.0001). Conclusions: The comprehensive list of CEA-positive human tumor types demonstrates that CEA is expressed in a broad range of epithelial neoplasms, many of which might benefit from CEA serum monitoring and anti-CEA therapies.