Colorectal cancer (CRC) is a leading global cause of illness and death. There is a need for identification of better prognostic markers beyond traditional clinical variables like grade and stage. Previous research revealed that abnormal expression of cytokeratin 7 (CK7) and loss of the intestinal-specific Special AT-rich sequence-binding protein 2 (SATB2) are linked to poor CRC prognosis. This study aimed to explore these markers' prognostic significance alongside two extraintestinal mucins (MUC5AC, MUC6), claudin 18, and MUC4 in 285 CRC cases using immunohistochemistry on tissue microarrays (TMAs). CK7 expression and SATB2-loss were associated with MUC5AC, MUC6, and claudin 18 positivity. These findings suggest a distinct "non-intestinal" immunohistochemical profile in CRC, often right-sided, SATB2-low, with atypical expression of CK7 and non-colorectal mucins (MUC5AC, MUC6). Strong MUC4 expression negatively impacted cancer-specific survival (hazard ratio = 2.7, p = 0.044). Genetic analysis via next-generation sequencing (NGS) in CK7 + CRCs and those with high MUC4 expression revealed prevalent mutations in TP53, APC, BRAF, KRAS, PIK3CA, FBXW7, and SMAD4, consistent with known CRC mutation patterns. NGS also identified druggable variants in BRAF, PIK3CA, and KRAS. CK7 + tumors showed intriguingly common (31.6%) BRAF V600E mutations corelating with poor prognosis, compared to the frequency described in the literature and databases. Further research on larger cohorts with a non-colorectal immunophenotype and high MUC4 expression is needed.

• Keywords
• Claudin 18, Colorectal carcinoma, Cytokeratin 7, Mucin, NGS, SATB2,
• MeSH
• Adult MeSH
• Phenotype MeSH
• Class I Phosphatidylinositol 3-Kinases genetics   metabolism   MeSH
• Immunohistochemistry * MeSH
• Keratin-7 metabolism   genetics   MeSH
• Colorectal Neoplasms * genetics   pathology   metabolism   mortality   MeSH
• Middle Aged MeSH
• Humans MeSH
• Mucin-4 genetics   metabolism   MeSH
• Mucin 5AC genetics   metabolism   MeSH
• Mucin-6 genetics   metabolism   MeSH
• Mutation MeSH
• Biomarkers, Tumor * genetics   metabolism   MeSH
• Prognosis MeSH
• Proto-Oncogene Proteins B-raf genetics   MeSH
• Proto-Oncogene Proteins p21(ras) genetics   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Transcription Factors MeSH
• Matrix Attachment Region Binding Proteins * genetics   metabolism   MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• BRAF protein, human MeSH Browser
• Class I Phosphatidylinositol 3-Kinases MeSH
• Keratin-7 MeSH
• KRAS protein, human MeSH Browser
• MUC4 protein, human MeSH Browser
• MUC5AC protein, human MeSH Browser
• MUC6 protein, human MeSH Browser
• Mucin-4 MeSH
• Mucin 5AC MeSH
• Mucin-6 MeSH
• Biomarkers, Tumor * MeSH
• PIK3CA protein, human MeSH Browser
• Proto-Oncogene Proteins B-raf MeSH
• Proto-Oncogene Proteins p21(ras) MeSH
• SATB2 protein, human MeSH Browser
• Transcription Factors MeSH
• Matrix Attachment Region Binding Proteins * MeSH

Colorectal carcinoma (CRC) is a disease that causes significant morbidity and mortality worldwide. To improve treatment, new biomarkers are needed to allow better patient risk stratification in terms of prognosis. This study aimed to clarify the prognostic significance of colonic-specific transcription factor special AT-rich sequence-binding protein 2 (SATB2), cytoskeletal protein cytokeratin 7 (CK7), and immune checkpoint molecule programmed death-ligand 1 (PD-L1). We analyzed a cohort of 285 patients with surgically treated CRC for quantitative associations among the three markers and five traditional prognostic indicators (i.e., tumor stage, histological grade, variant morphology, laterality, and mismatch-repair/MMR status). The results showed that loss of SATB2 expression had significant negative prognostic implications relative to overall survival (OS) and cancer-specific survival (CSS), significantly shortened 5 years OS and CSS and 10 years CSS in patients with CRC expressing CK7, and borderline insignificantly shortened OS in patients with PD-L1 + CRC. PD-L1 showed a significant negative impact in cases with strong expression (membranous staining in 50-100% of tumor cells). Loss of SATB2 was associated with CK7 expression, advanced tumor stage, mucinous or signet ring cell morphology, high grade, right-sided localization but was borderline insignificant relative to PD-L1 expression. CK7 expression was associated with high grade and SATB2 loss. Additionally, a separate analysis of 248 neoadjuvant therapy-naïve cases was performed with mostly similar results. The loss of SATB2 and CK7 expression were significant negative predictors in the multivariate analysis adjusted for associated parameters and patient age. In summary, loss of SATB2 expression and gain of CK7 and strong PD-L1 expression characterize an aggressive phenotype of CRC.

• MeSH
• B7-H1 Antigen genetics   metabolism   MeSH
• Keratin-7 genetics   MeSH
• Colorectal Neoplasms * pathology   MeSH
• Humans MeSH
• Biomarkers, Tumor metabolism   MeSH
• Prognosis MeSH
• Transcription Factors genetics   MeSH
• Matrix Attachment Region Binding Proteins * genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• B7-H1 Antigen MeSH
• CD274 protein, human MeSH Browser
• Keratin-7 MeSH
• Biomarkers, Tumor MeSH
• SATB2 protein, human MeSH Browser
• Transcription Factors MeSH
• Matrix Attachment Region Binding Proteins * MeSH

Trophoblastic cell surface antigen 2 (TROP2) is a membrane glycoprotein overexpressed in many solid tumors with a poor prognosis, including intestinal neoplasms. In our study, we show that TROP2 is expressed in preneoplastic lesions, and its expression is maintained in most colorectal cancers (CRC). High TROP2 positivity correlated with lymph node metastases and poor tumor differentiation and was a negative prognostic factor. To investigate the role of TROP2 in intestinal tumors, we analyzed two mouse models with conditional disruption of the adenomatous polyposis coli (Apc) tumor-suppressor gene, human adenocarcinoma samples, patient-derived organoids, and TROP2-deficient tumor cells. We found that Trop2 is produced early after Apc inactivation and its expression is associated with the transcription of genes involved in epithelial-mesenchymal transition, the regulation of migration, invasiveness, and extracellular matrix remodeling. A functionally similar group of genes was also enriched in TROP2-positive cells from human CRC samples. To decipher the driving mechanism of TROP2 expression, we analyzed its promoter. In human cells, this promoter was activated by β-catenin and additionally by the Yes1-associated transcriptional regulator (YAP). The regulation of TROP2 expression by active YAP was verified by YAP knockdown in CRC cells. Our results suggest a possible link between aberrantly activated Wnt/β-catenin signaling, YAP, and TROP2 expression.

• Keywords
• APC, EMT, TACSTD2, WNT/β-catenin signaling, colorectal cancer, expression profiling, organoids,
• Publication type
• Journal Article MeSH