Disease relevance of KRT20

• Circulating colorectal cancer cell positivity rose from 48% (CEA) and 34% (CK20) with one assay of one sample to 74% when both assays of three samples were used to identify circulating tumor cells [1].
• All primary lung adenocarcinomas with rootlets were CK7(+) CK20(-), and six of nine (67%) were V(+) [2].
• The expression of CK 20 was virtually absent in carcinomas from other organ systems and in malignant mesothelioma [3].
• Cytokeratin 20 expression was similar in primary ovarian tumors (83%) and metastases of upper (89%; P=0.071) and lower gastrointestinal tract origin (93%; P=0.29) [4].
• Positive expression of CK20 in primary small cell carcinoma of the vagina might represent a Merkel cell carcinoma subtype of this tumor [5].
• Dysregulation of CK20 expression is an early event in the carcinogenesis of papillary noninvasive bladder cancer, but occurs later than FGFR3 mutations [6].

Psychiatry related information on KRT20

• The antigen identified by K20 was thought to belong to the integrins, a family of cell surface receptors that play a role in cell adhesion, cell interactions, wound healing, and immune defense mechanisms [7].
• If therapeutic decision-making depends on differential diagnostic analysis, examination of CK 20 expression appears to be helpful [8].

High impact information on KRT20

• The crystal structure reveals the basis of the specificity of the enzyme for H4-K20 because a histidine residue within the substrate, close to the target lysine, is required for completion of the active site [9].
• These results establish the HCF-1C subunit as an important M phase regulator and suggest that H4-K20 methylation status contributes to chromosome behavior during mitosis and proper cytokinesis [10].
• Here, we show that HCF-1C subunit depletion causes extensive mitotic defects, including a switch from monomethyl to dimethyl lysine 20 of histone H4 (H4-K20) and defective chromosome alignment and segregation [10].
• Indeed, upregulation of PR-Set7 expression upon loss of HCF-1 leads to improper mitotic H4-K20 methylation and cytokinesis defects [10].
• Analysis of reaction products by reverse phase high performance liquid chromatography and gas phase sequencing demonstrated the exclusive myristyl acylation of K19 and K20, consistent with the presence in monocytes of a specific lysyl N-epsilon-NH2-myristyl transferase activity [11].

Chemical compound and disease context of KRT20

• Immunohistochemical staining for CK7 and CK20 was performed on formalin-fixed paraffin-embedded tissues containing primary cancers and lymph node metastases [12].
• Cylindromas of the breast and skin did not express cytokeratin 20, gross cystic disease fluid protein 15, or estrogen or progesterone receptor [13].
• Carcinoembryonic antigen and/or cytokeratin 20 identified bronchogenic, gastric, pancreatic and colorectal carcinomas versus breast carcinomas lacking gross cystic disease fluid protein 15 and oestrogen or progesterone receptors with a sensitivity, specificity and predictive accuracy of 0.82, 0.99 and 0.95, respectively [14].
• In this study, we combined this Adv (Adv-E1AdB) with a fiber mutation, F/K20, which has a stretch of 20 lysine residues added at the COOH-terminus of the fiber and shows high transduction efficiency to gliomas [15].
• The tumor in the second case consisted of an AFP-positive glandular YST, with a glandulopapillary pattern closely resembling fetal lung type adenocarcinoma, coexisting with an AFP-negative, cytokeratin 20-positive, atypical MC; transitional areas between the two components were also seen [16].

Biological context of KRT20

• Our results also indicate that regulation of CK20 gene expression involves molecular pathways that are altered by MSI-H [17].
• In this study, we evaluated the immunohistochemical expression of TTF-1, CK 7, and CK 20 in 67 BACs (48 nonmucinous, 12 mucinous, and 7 of mixed histology) [18].
• Reduced expression of cytokeratin 20 in colorectal carcinomas with high levels of microsatellite instability [17].
• Quantitative estimation of CEA and CK20 expression in tumour tissue of colorectal cancer and its liver metastases with reverse transcription and real-time PCR [19].
• Our study indicates that quantitative real-time RT-PCR detection for CEA, CK20 and CK19 mRNA in peripheral blood is a valuable tool for monitoring early stage dissemination of CRC cells in blood circulation [20].

Anatomical context of KRT20

• Lymph node levels of CEA and CK20 mRNA correlated strongly (p < 0.0001, r = 0.8) [21].
• In 7 of 15 cases containing CK20-positive Merkel cells, CK7 was also seen to stain Merkel cells [22].
• While normal small intestinal mucosa was diffusely positive for CK20 and completely negative for CK7 expression, all small intestinal adenocarcinomas (24 of 24) showed a variable degree of CK7 expression [23].
• Alteration of cytokeratin 7 and cytokeratin 20 expression profile is uniquely associated with tumorigenesis of primary adenocarcinoma of the small intestine [23].
• We also demonstrate that CK7, but not CK20, highlights intraepidermal clear cells with bland nuclear features (Toker cells) that have been reported in 11% of normal nipples [22].

Associations of KRT20 with chemical compounds

• CK7 and CK20 have limited utility in distinguishing HCC from CC or MA, and Factor XIII-A is not useful [24].
• The expression of laminin-1 chains (beta1 and gamma1), laminin-2 (merosin), integrin receptors to laminin (alpha3beta1 and alpha6beta4) and cytokeratin (CK20) were studied by immunohistochemical methods in gastric biopsies from antrum of 25 patients [25].
• All the tumors were negative for CK20, estrogen and progesterone receptors, Her2Neu, and p53 [26].
• Paraffin-embedded tissue from the ovary and jejunum was stained with hematoxylin and eosin, as well as with immunohistochemical stains for cytokeratin 20 and cytokeratin 7 [27].
• Tumor-suspect nodules previously considered disease free by HE stain on whole-mount section were examined by in situ hybridization (ISH) on tissue microarray (TMA) through detecting mRNAs of CEA and CK20 with non radioactive biotin-tagged oligonucleotide probes [28].

Enzymatic interactions of KRT20

• CDX2 expression (at 10% and 50% cut-off levels) and the CK20/CK7 pattern of the metastases were correlated to the primary site established [29].

Co-localisations of KRT20

• Cytokeratin 20 (CK 20) colocalized with KGFR [30].

Regulatory relationships of KRT20

• The neoplastic tissue showed marked positivity for CEA and expressed cytokeratin 20, confirming the diagnosis of metastases to the maxillary sinus from colorectal adenocarcinoma [31].

Other interactions of KRT20

• Quantification of cytokeratin 20, carcinoembryonic antigen and guanylyl cyclase C mRNA levels in lymph nodes may not predict treatment failure in colorectal cancer patients [32].
• Although the CK7/CK20 immunoprofile is a valuable diagnostic marker for differentiating primary lung adenocarcinoma from metastatic colonic adenocarcinoma, caution should be exercised when dealing with mucinous BAC [33].
• Primary ovarian tumors expressed CDX2 (40%) less frequently than cytokeratin 20 (83%) (P<0.0001) [4].
• In the AUS group, 47% demonstrated abnormal CK20 and increased Ki-67 expression, suggestive of urothelial dysplasia/CIS, 29% were negative with both, suggestive of RUA, and the remaining 24% cases could not be resolved [34].
• Cytokeratin 20, AN43, PGDH, and COX-2 expression in transitional and squamous cell carcinoma of the bladder [35].

Analytical, diagnostic and therapeutic context of KRT20

• In this study, we compared real-time RT-PCR for CEA and CK20 and analysed patients with metastatic disease (n=32) and healthy volunteers (n=17) [36].
• CK20 mean values were elevated in cancer patients (P<0.001) and defined a subgroup (38%) who showed CK20 levels at least 100-fold above the highest value of the healthy control group [36].
• We surveyed 435 epithelial neoplasms from various organ systems by immunohistochemistry using CK 7 and CK 20 monoclonal antibodies [3].
• CEA or CK-20 or GCC-specific polymerase chain reaction (PCR) was carried out on mRNA transcripts extracted from the nodal tissues [37].
• Detection of CK-20 and CEA mRNA correlated in nine of 12 cases (75.0%) with the risk of tumour recurrence (not significant) and showed a tendency towards shorter disease-free survival by univariate analysis (not significant) [38].

References