KL-6 is another useful marker in assessing a micropapillary pattern in carcinomas of the breast and urinary bladder, but not the colon

Role of microRNA in colorectal carcinoma (CRC): a narrative review

MicroRNAs (miRNAs) are short non-coding RNAs that play a critical role in regulating gene expression by binding to target messenger RNAs (mRNAs). They were first discovered around 8 years after the identification of the first miRNA in 1993, and since then, there has been a significant increase in miRNA-related research and discoveries. MiRNAs have been implicated in various biological processes, including cancer, particularly in colorectal cancer (CRC). In CRC, miRNAs act as either oncogenes or tumor suppressors, influencing essential cellular functions such as cell proliferation, apoptosis, angiogenesis, and metastasis. The dysregulation of miRNAs in CRC can arise from different factors, leading to abnormal expression levels of their target mRNAs and subsequently affecting protein production. Consequently, miRNAs may directly target oncogenes or tumor suppressor genes, thereby contributing to cancer initiation and progression. Notably, tumors often exhibit reduced expression of mature miRNAs. In CRC research, miRNAs offer potential as diagnostic biomarkers and therapeutic targets. Specific miRNA profiles could serve as non-invasive tools for early CRC detection and risk assessment. Additionally, miRNA-based therapies present a promising approach for targeted cancer treatment by modulating miRNA expression. However, challenges related to delivery systems and long-term safety must be addressed to fully harness their therapeutic potential.

A case of marked rectal stenosis due to Douglas' pouch metastasis of renal pelvic carcinoma successfully treated with salvage enfortumab vedotin: correlation between serum KL-6 levels and tumor response

Introduction

We report a rare case of marked rectal stenosis due to Douglas' pouch metastasis of renal pelvic urothelial carcinoma successfully treated with enfortumab vedotin.

Case presentation

A 77-year-old female presented with difficulty in defecation and abdominal distension. She had received two courses of cisplatin plus gemcitabine followed by four courses of maintenance avelumab for postoperative lymph node metastasis of renal pelvic urothelial carcinoma. KL-6 levels were elevated, and a computed tomography scan revealed an irregularly shaped large mass occupying Douglas' pouch, with marked rectal stenosis. Metastatic urothelial carcinoma was pathologically diagnosed, and enfortumab vedotin was initiated after colostomy. After 12 courses of enfortumab vedotin, metastatic lesions showed marked shrinkage and KL-6 levels decreased.

Conclusion

Enfortumab vedotin elicited a remarkable response in treating rectal stenosis due to metastasis of renal pelvic urothelial carcinoma in Douglas' pouch. Furthermore, serum KL-6 levels were correlated with the severity of metastatic urothelial carcinoma.

Serum KL-6 levels predict clinical outcomes and are associated with MUC1 polymorphism in Japanese patients with COVID-19

BACKGROUND

Krebs von den Lungen-6 (KL-6) is a known biomarker for diagnosis and monitoring of interstitial lung diseases. However, the role of serum KL-6 and the mucin 1 (MUC1) variant (rs4072037) in COVID-19 outcomes remains to be elucidated. We aimed to evaluate the relationships among serum KL-6 levels, critical outcomes and the MUC1 variant in Japanese patients with COVID-19.

METHODS

This is a secondary analysis of a multicentre retrospective study using data from the Japan COVID-19 Task Force collected from February 2020 to November 2021, including 2226 patients with COVID-19 whose serum KL-6 levels were measured. An optimal serum KL-6 level cut-off to predict critical outcomes was determined and used for multivariable logistic regression analysis. Furthermore, the relationship among the allele dosage of the MUC1 variant, calculated from single nucleotide polymorphism typing data of genome-wide association studies using the imputation method, serum KL-6 levels and COVID-19 critical outcomes was evaluated.

RESULTS

Serum KL-6 levels were significantly higher in patients with COVID-19 with critical outcomes (511±442 U/mL) than those without (279±204 U/mL) (p<0.001). Serum KL-6 levels ≥304 U/mL independently predicted critical outcomes (adjusted OR (aOR) 3.47, 95% CI 2.44 to 4.95). Moreover, multivariable logistic regression analysis with age and sex indicated that the MUC1 variant was independently associated with increased serum KL-6 levels (aOR 0.24, 95% CI 0.28 to 0.32) but not significantly associated with critical outcomes (aOR 1.11, 95% CI 0.80 to 1.54).

CONCLUSION

Serum KL-6 levels predicted critical outcomes in Japanese patients with COVID-19 and were associated with the MUC1 variant. Therefore, serum KL-6 level is a potentially useful biomarker of critical COVID-19 outcomes.

Histology of Colorectal Carcinoma: Proven and Purported Prognostic Factors

Although tumor stage has a profound influence on prognosis, several histologic features are also important. These parameters predict biological behavior and can be used by clinicians to determine whether patients are at high risk for disease progression and, thus, are candidates for adjuvant therapy, particularly when they have localized (ie, stage II) disease. This article summarizes the evidence supporting the prognostic values of various histologic parameters evaluated by pathologists who assign pathologic stage to colorectal cancers. Criteria to be discussed include histologic subtype, tumor grade, lymphatic and perineural invasion, tumor budding, and host immune responses.

Serum Krebs von den Lungen-6 level in the disease progression and treatment of Mycobacterium avium complex lung disease

BACKGROUND AND OBJECTIVE

The lack of useful biomarkers reflecting the disease state limits the management of Mycobacterium avium complex lung disease (MAC-LD). We clarified the associations between serum KL-6 level, disease progression and treatment response.

METHODS

Resected lung tissues from MAC-LD patients were immunostained for KL-6. We compared serum KL-6 levels between MAC-LD and healthy control or bronchiectasis patients without nontuberculous mycobacterial lung disease (NTM-LD). Serum KL-6 level was assessed in a prospective observational study at Keio University Hospital between May 2012 and May 2016. We investigated associations between serum KL-6 level and disease progression and treatment response in patients untreated for MAC-LD on registration (n = 187).

RESULTS

The KL-6⁺ alveolar type 2 cell population in the lung and serum KL-6 level were significantly higher in MAC-LD patients than in controls. Serum KL-6 level in bronchiectasis patients without NTM-LD showed no significant increase. Of the 187 patients who did not receive treatment on registration, 53 experienced disease progression requiring treatment. Multivariable Cox analysis revealed that the serum KL-6 level (aHR: 1.18, P = 0.005), positive acid-fast bacilli smear (aHR: 2.64, P = 0.001) and cavitary lesions (aHR: 3.01, P < 0.001) were significantly associated with disease progression. The change in serum KL-6 (ΔKL-6) was significantly higher in the disease progression group; it decreased post-treatment, reflecting the negative sputum culture conversion.

CONCLUSION

Serum KL-6 level is associated with disease progression and treatment response. Longitudinal assessment combined with AFB smear status and presence of cavitary lesions may aid MAC-LD management.

Prognostic and therapeutic role of HER2 expression in micropapillary carcinoma of the bladder

Micropapillary carcinoma of the bladder (MPBC) is a variant type of infiltrating urothelial carcinoma, which portends a poor biological behavior in terms of disease stage at first diagnosis and clinical outcome; its peculiar morphology raises issues concerning the ability of tumor detection by imaging techniques and proper biopsy procedure, and the appropriate treatment for non-muscle infiltrating and muscle-infiltrating MPBC remains a matter of debate. On the basis of its established prognostic and therapeutic role in breast and gastro-esophageal cancer in the first instance, the human epidermal growth factor receptor-2 (HER2) has been investigated in selected case series of MPBC over the last 10 years. The aim of the present review was to summarize the existing evidence on HER2 status in MPBC, and to discuss its present and future utility in risk assessment and treatment choice of this uncommon, yet aggressive, disease.

Reversed polarity of the glandular epithelial cells in micropapillary carcinoma of the large intestine and the EMA/MUC1 immunostain

Micropapillary carcinoma of the colon and rectum is associated with an adverse prognosis. This tumour type displays reverse polarity of the tumour cells and is stated to be characterised by an inside-out epithelial membrane antigen (EMA)/MUC1 staining. Nine cases of primary colorectal carcinoma and one omental metastasis were studied by means of immunohistochemistry, using antibodies to detect EMA, MUC1, MUC2, MUC3, MUC5AC, MUC6, CD10, CA125, carcinoembryonic antigen (CEA). The inside-out pattern staining with EMA/MUC1 ranged from diffuse circumferential through focal and partial to negative, but in some cases CEA, MUC3 and CD10 also showed this pattern staining, sometimes more clearly than did EMA or MUC1. The reverse polarity of colorectal micropapillary carcinomas is sometimes better visualised by immunostains other than EMA/MUC1.

Role of Urinary Biomarkers in the Diagnosis of Adenoma and Colorectal Cancer: A Systematic Review and Meta-Analysis

The growing interest in enhancing and spreading colorectal cancer (CRC) screening has been stimulating the exploration of novel biomarkers with greater sensitivity and specificity than immunochemical faecal occult blood test (iFOBT). The present study provides i) a systematic review of the urinary biomarkers that have been tested to achieve early CRC diagnosis and assess the risk of colorectal adenoma and adenocarcinoma, and ii) a meta-analysis of the data regarding the urinary prostaglandin (PG) metabolite PGE-M. As regard to gene markers, we found significantly different percent methylation of the vimentin gene in CRC patients and healthy controls (HC) (p<0.0001). Respect to metabolism of nitrogenous bases, cytidine, 1-methyladenosine, and adenosine, have higher concentrations in CRC patients than in HC (respectively, p<0.01, p=0.01, and p<0.01). As regard to spermine we found that N1,N12 diacetyl spermine (DiAcSpm) and N1, N8 diacetylspermidine (DiAcSpd) were significantly higher in CRC than in HC (respectively p=0.01 and p<0.01). Respect to PGE-M, levels were higher in CRC than in those with multiple polyposis (p<0.006) and HC subjects (p<0.0004). PGE-M seems to be the most interesting and promising urinary marker for CRC and adenoma risk assessment and for CRC screening. In conclusion, evidence suggests that urinary biomarker could have a potential role as urinary biomarkers in the diagnosis of colorectal cancer. Particularly, PGE-M seems to be the most promising urinary marker for CRC early detection.

Consensus and conflict in invasive micropapillary carcinoma: a case report and review of the literature

Invasive micropapillary carcinoma (IMPC) is an aggressive histologic subtype of adenocarcinoma that has been gaining increased attention over the past twenty years. It is important to recognize IMPC due to its strong association with early lymphovascular invasion (LVI), high risk of lymph node metastasis, perineural invasion and poor prognosis. Controversies regarding IMPC include differentiating from retraction artifact and mimics, clinical significance of proportion of micropapillary component (MC), pathogenesis, biologic nature of the entity and consequently terminology, etc. We herein present a case of rectal IMPC arising from a tubulovillous adenoma. Since HER2 over-expression has been reported in IMPC of the breast and the bladder but never in the colorectum, given the availability of HER2 targeted therapy, HER2 protein expression in our case is examined by immunohistochemical study which shows weak incomplete membrane staining in less than 5% of cells. Literature is reviewed with emphasis on colorectal IMPC as well as aforementioned controversial topics. In summary, more study is needed to resolve the conflicts and build consensus on IMPC.

Peritoneal Malignant Mesothelioma with Epithelioid Type, Demonstrating High Serum and Ascitic KL-6 Levels: Immunohistochemical Analyses

We report a case of KL-6 producing peritoneal malignant mesothelioma. A 56-year-old woman was referred to our hospital on November 2005 with severe abdominal distention. Peritoneal malignant mesothelioma with epithelioid type was diagnosed by clinical symptoms, laboratory investigations, imaging studies, and immunohistochemical examination of known tumor markers. In addition, high serum and ascitic KL-6 levels were observed and the immunostaining of the tumor for KL-6 was evident. We thus consider KL-6 to be a potential novel marker for peritoneal malignant mesothelioma with epithelioid type.

Gastric carcinoma with an invasive micropapillary carcinoma component showing HER2 gene amplification and CD10 expression: a case report and review of the literature

An 81-year-old man was referred to our hospital because gastric cancer was detected on screening esophagogastroduodenoscopy. Surgical resection of the tumor was performed. It was 25 × 20 mm in size and swollen lymph nodes were present nearby. Lymphadenectomy was also performed. Histopathologically, the tumor reached the proper muscle layer via venous invasion. There were three components that constituted the tumor, that is, 40% of mass was invasive micropapillary carcinoma (IMPC), 40% was papillary adenocarcinoma and 20% tubular adenocarcinoma. Vascular invasion was prominent. Immunohistochemistry revealed that the tumor showed an entirely intestinal mucin phenotype, being positive only for CD10 and negative for MUC2, MUC5AC, and MUC6. HER2 staining score ranged from 2+ to 3+, depending on the components described above. HER2 gene amplification was present in all the components according to dual-color in situ hybridization. The metastatic lymph nodes were similar to the primary site in morphology and immunohistochemistry, but HER2 amplification was higher in the lymph nodes. The IMPC component with HER2 amplification is rarely seen and its positivity for CD10 is an unexpected finding for gastric IMPC. Hence, this is a highly unusual case judging by the literature; further studies are needed to clarify the nature of gastric IMPC.

Usefulness of KL-6 in the subtyping of intraductal papillary mucinous neoplasia of the pancreas, including carcinoma, dysplasia, and hyperplasia

KL-6 is known as a useful serum biomarker of the disease activity in interstitial pneumonias. We investigated its usefulness as a biomarker for subtyping intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. IPMNs are generally divided into 4 subtypes, namely pancreatobiliary (PB), intestinal (INT), gastric (GS), and oncocytic (ONC). Aside from the KL-6 antibody, the MUC1, MUC2, MUC5AC, MUC6, and MIB-1 antibodies were also examined. Eighteen IPMN cases were examined, including 12 cases of intraductal papillary mucinous carcinomas (IPMCs) simultaneously associated with dysplasia (IPMDs) and hyperplasia (IPMHs) and 6 IPMD cases with IPMH. KL-6 antibody was positive in the 8 IPMC cases, corresponding to a MUC2-negative PB subtype, but negative in 4 IPMC cases, corresponding to the INT subtype, which is positive for MUC2. IPMD of moderate-to-severe degree positively stained for the KL-6 antibody in the IPMC cases of the PB subtype but not in those of the INT subtype. The IPMH cases were mostly negative for KL-6, similar to the mild IPMD cases. In the 6 cases of mild IPMD and/or IPMH, KL-6 and MUC2 expressions were mostly negative. In conclusion, the KL-6 antibody is immunohistochemically a good biomarker of the PB subtype of IPMC, but not the INT subtype. Identifying IPMN subtypes based on KL-6 stainability would be useful. Clinicopathological studies with more IPMC cases might be needed for further progress in this field of study.

Immunohistochemical analysis of invasive micropapillary carcinoma pattern in four cases of gastric cancer

Gastric cancer with the invasive micropapillary carcinoma (IMPC) pattern has been reported to be a variant with poor prognosis and rapid progression. To the best of our knowledge, only 4 cases of gastric cancer from Japan and 11 cases from Korea have been reported to contain the IMPC pattern. In the present study, 4 cases of gastric cancer containing the IMPC pattern from 2 Japanese men and 2 Japanese women are reported. The cancer tissues, including a recurrent lesion in 1 case and lymph node metastases in 2 other cases, were examined immunohistochemically to identify suitable markers for demonstrating the peculiar "inside out" pattern of IMPC and for analyzing HER2 expression. A characteristic IMPC pattern occupied more than 10% of each cancer tissue in these 4 cases. Lymphatic invasions were very often detected; in fact, lymph node metastases were detected in 3 out of 4 cases. The unique "inside out" pattern in IMPC was clearly revealed in all cases by staining with antibodies to both epithelial membrane antigen (EMA) and KL-6, but not with an antibody to CD10. HER2 was positive in 3 of 4 cases with the IMPC pattern, including cases with a recurrent lesion or lymph node metastases. Fluorescence in situ hybridization (FISH) analyses disclosed positive results in case 1, and case 3 including lymph node metastatic foci. Highest FISH titer was 6.8 in case 1, revealing marked amplification of HER-2 gene. Four cases of gastric cancer with the IMPC pattern were reported. EMA and KL-6, but not CD10, were particularly useful markers for visualizing the characteristic "inside out" pattern of the IMPC pattern in stomach cancers, similar to the markers for breast and urinary bladder cancers.

Micropapillary urothelial carcinoma: Cytologic features in a retrospective series of urine specimens

Background:

The micropapillary variant of urothelial carcinoma (uPC) is a rare variant of urothelial carcinoma that carries a poor prognosis. Definitive surgery may represent optimal management of low stage tumors. Urine cytology is indispensable in the screening and follow-up of urinary tract cancer. However, cytopathological criteria for diagnosis of uPC and its differentiation from conventional urothelial carcinoma (CUC) are not well-defined.

Materials and Methods:

Twenty-five cases of histologically confirmed micropapillary uPC from 21 patients were compared to 25 cases of histologically confirmed high-grade CUC.

Results:

In uPC cases, cell clusters were identified in 13 of 25 specimens from 10 patients. Six of the 13 specimens containing cell clusters corresponded to surgical pathology specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. In contrast, only 1 of the 12 urine specimens devoid of cell clusters corresponded to surgical specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. Cytomorphologic features of urinary specimens from patients with histologically confirmed micropapillary carcinoma were generally similar to those from patients with high-grade CUC, making it difficult to distinguish these entities in exfoliative urine specimens.

Conclusions and Summary:

Further investigation of the core cytopathological characteristics of uPC is warranted to refine its diagnostic criteria by exfoliative urine cytology.

Micropapillary variant of urothelial carcinoma

Micropapillary carcinoma (MPC) of urinary tract is an uncommon variant of urothelial carcinoma with significant diagnostic and prognostic implications. Though MPC shows characteristic microscopic features, there exists interobserver variability and also it needs to be differentiated from the metastasis from other organs. The prognosis is generally poor, depending on the proportion of the micropapillary component in some reports. Early cystectomy in cases with only lamina propria invasion may be indicated according to recent studies. This review outlines the general features of this entity and briefly comments on the controversies and the recent development.

Invasive micropapillary carcinoma of the ascending colon--a report of a case

Micropapillary carcinoma (MC) has been recently recognized to be a rare but distinctive variant of adenocarcinoma. At present, only a limited number of colorectal MC cases have been reported. We present a case of MC of the ascending colon with distant metastasis. A 61-year-old female patient was hospitalized with a complaint of abdominal pain. A diagnostic work-up revealed cancer of the ascending colon with multiple lung metastases. The patient underwent a right hemicolectomy with lymph node dissection. A peritoneal nodule was observed in the abdominal cavity during surgery, and this nodule was also resected. The pathologic findings of the colon tumor revealed components of conventional tubular adenocarcinoma and micropapillary carcinoma. Lymph nodes and a peritoneal nodule revealed tubular adenocarcinoma. MC is a rare disease but has high malignant potential. In the present case the tumor was small in size, but the patient had a peritoneal and multiple lung metastases.

Emerging concepts in micropapillary urothelial carcinoma

Micropapillary urothelial carcinoma is a relatively uncommon variant of urothelial carcinoma, but its recognition carries important prognostic and treatment implications. Micropapillary morphology occurs in neoplasms arising in many different organ systems and displays aggressive biologic behavior regardless of its site of origin. On account of this association, micropapillary features in urothelial carcinoma should be reported regardless of whether the pattern is focal or dominant. The overall prognosis for micropapillary urothelial carcinoma is poor and recent studies suggest that early treatment with cystectomy could improve outcome, as these tumors are unlikely to respond to chemotherapy when used as a secondary treatment modality. This review discusses the histologic features required for diagnosis and the clinical significance of rendering a diagnosis of micropapillary urothelial carcinoma.