Cytokeratins in the Histological Diagnosis of Malignant Tumors

Keratin K6irs is specific to the inner root sheath of hair follicles in mice and humans

BACKGROUND

Keratins are a multigene family of intermediate filament proteins that are differentially expressed in specific epithelial tissues. To date, no type II keratins specific for the inner root sheath of the human hair follicle have been identified.

OBJECTIVES

To characterize a novel type II keratin in mice and humans.

METHODS

Gene sequences were aligned and compared by BLAST analysis. Genomic DNA and mRNA sequences were amplified by polymerase chain reaction (PCR) and confirmed by direct sequencing. Gene expression was analysed by reverse transcription (RT)-PCR in mouse and human tissues. A rabbit polyclonal antiserum was raised against a C-terminal peptide derived from the mouse K6irs protein. Protein expression in murine tissues was examined by immunoblotting and immunofluorescence.

RESULTS

Analysis of human expressed sequence tag (EST) data generated by the Human Genome Project revealed a fragment of a novel cytokeratin mRNA with characteristic amino acid substitutions in the 2B domain. No further human ESTs were found in the database; however, the complete human gene was identified in the draft genome sequence and several mouse ESTs were identified, allowing assembly of the murine mRNA. Both species' mRNA sequences and the human gene were confirmed experimentally by PCR and direct sequencing. The human gene spans more than 16 kb of genomic DNA and is located in the type II keratin cluster on chromosome 12q. A comprehensive immunohistochemical survey of expression in the adult mouse by immunofluorescence revealed that this novel keratin is expressed only in the inner root sheath of the hair follicle. Immunoblotting of murine epidermal keratin extracts revealed that this protein is specific to the anagen phase of the hair cycle, as one would expect of an inner root sheath marker. In humans, expression of this keratin was confirmed by RT-PCR using mRNA derived from plucked anagen hairs and epidermal biopsy material. By this means, strong expression was detected in human hair follicles from scalp and eyebrow. Expression was also readily detected in human palmoplantar epidermis; however, no expression was detected in face skin despite the presence of fine hairs histologically.

CONCLUSIONS

This new keratin, designated K6irs, is a valuable histological marker for the inner root sheath of hair follicles in mice and humans. In addition, this keratin represents a new candidate gene for inherited structural hair defects such as loose anagen syndrome.

Metastatic adenocarcinoma of the esophagus to the skin: new patterns of tumor recurrence and alternate treatments for palliation

BACKGROUND

Esophageal cancer, particularly adenocarcinoma of the esophagus (ACE), has been steadily increasing in incidence in the United States. In the past, patients usually died rapidly with locoregional disease that leads to inanition and aspiration. However, today when patients with ACE are treated successfully with induction chemotherapy and radiation therapy, followed by surgical excision, ACE usually does not recur locally, but presents with metatastic disease. We present a 62-year-old white male with ACE, which was treated with induction chemotherapy and radiation therapy followed by surgical excision. After approximately 1 year with no evidence of locoregional recurrence, the patient presented with diffuse cutaneous metastatic disease.

METHODS

In addition to routine staining immunohistochemical stains for CK(AE1/AE3), CK7, CK 20, EMA, alpha-smooth muscle (SM) actin, S-100 protein, CD34, P53, Bcl-2, c-erbB-2 were performed.

RESULTS

The immunohistochemical profile was consistent with an esophageal origin showing positive staining with CK20 and CK7 as well as AE1/AE3 and EMA. In addition, there was marked nuclear expression of p53, as well as membrane expression of c-erb-B2; consistent with progression of the disease and poor response to further cytotoxic therapeutic regimes.

CONCLUSIONS

With new therapeutic protocols, we can expect to see more metastatic disease with recurrences of ACE. The histopathologic features and the immunohistochemical profile of the recurrent tumors may be helpful in determining alternate forms of therapy that either alone or in combination could be useful in palliation and delaying progression.

WT1 is an integral component of an antibody panel to distinguish pancreaticobiliary and some ovarian epithelial neoplasms

We investigated whether a panel of antibodies including WT1 could separate pancreaticobiliary and ovarian carcinomas by staining 64 pancreaticobiliary adenocarcinomas, 41 ovarian serous carcinomas, and 12 primary ovarian mucinous neoplasms with WT1, cytokeratin (CK) 17, CK20, carcinoembryonic antigen (CEA), and CA-125. Moderate or strong intensity reactivity in more than 25% of cells was a positive result. Of the ovarian serous carcinomas, 38 (93%) were WT1 reactive and 22 (54%) WT1 positive, 9 (22%) had CK20 reactivity, and 3 (7%) were CK20 positive in fewer than 50% of cells. All were CK17 or CEA nonreactive. Of the ovarian mucinous neoplasms, all were WT1 and CK17 nonreactive and 11 (92%) were CEA reactive, 8 (67%) CEA positive, 10 (83%) CK20 reactive, and 6 (50%) CK20 positive. Of the pancreaticobiliary adenocarcinomas, 19 (30%) were CK20 positive, 27 (42%) CK17 positive, and 52 (81%) CEA positive. All were WT1 nonreactive. A panel including WT1, CK17, CK20, and CEA is useful to distinguish pancreaticobiliary and ovarian serous carcinomas. Extensive CK17 reactivity is supportive of a pancreaticobiliary adenocarcinoma when the differential diagnosis includes ovarian mucinous neoplasm. None of the antibodies positively identified ovarian mucinous neoplasms.

Technical aspects of minimal residual disease detection in carcinoma patients

The burden of occult malignant cells which remains after a course of treatment that has resulted in clinical remission is referred to as minimal residual disease (MRD). MRD is increasingly considered as a determinant of local or systemic recurrence in cancer patients. During the last 20 years, methods for the detection of rare cancer cells have evolved from mere cytomorphological investigations to a variety of immunological and molecular assays. Since surgical therapy remains the best treatment option for cancer patients with resectable tumors, the first question to address is whether the removal of the tumor was complete or some cancer cells remained from the tumor at the primary site. Several tumor-associated DNA alterations have been identified to solve this diagnostic problem. Assays detecting tumor-associated DNA alterations have been applied to resection margins and body fluids such as bronchoalveolar lavage, sputum, urine, pancreatic juice, colonic lavage, and stool. Due to the higher sensitivity of immunocytochemical and reverse-transcriptase polymerase chain reaction (RT-PCR)-based assays, the second question to be addressed is whether systemic hematogenous or lymphatic spread of cancer cells occurred. Disseminated cancer cells have been detected in bone marrow aspirates, peripheral blood, and lymph node biopsies, and cancer cell dissemination is regarded as a relevant and independent prognostic factor. Thus, sensitive techniques for the detection of MRD are likely to guide indications for surgical or adjuvant therapy protocols in clinical oncology. However, since many of the assays for the detection of MRD are complex, and results are influenced by a variety of technical aspects, the majority of diagnostic applications have not yet been sufficiently standardized. Consequently, quality control and reproducibility of minimal disease detection assays remain unsolved problems. Therefore, well controlled collaborative studies are urgently required to evaluate indications and diagnostic standards for these assays. This review summarizes technical aspects and their implications for the clinical application of presently available assays for MRD detection in carcinoma patients.

Epithelial cells in the peripheral blood of patients with cancer of the head and neck: incidence, detection and possible clinical significance

In this study amplification of cytokeratin-19 mRNA by Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect circulating tumor cells in the peripheral blood of patients with cancer of the head and neck before, during and after radiation therapy. Detection of cytokeratin-19-positive cells coincided with local failure, distant metastasis and anemia.

Cytokeratins 7, 17, and 20 reactivity in pancreatic and ampulla of vater adenocarcinomas. Percentage of positivity and distribution is affected by the cut-point threshold

We studied reactivity of cytokeratins (CK) 7, 17, and 20 in 64 pancreaticobiliary adenocarcinomas to examine the effect of different cut-point thresholds on "positive" results, compare ampulla of Vater and pancreas adenocarcinomas, and provide additional experience with CK17 reactivity. Almost all neoplasms had extensive CK7 reactivity. The number of CK20-positive cases decreased from 29 (45%; any stained cells) to 19 (30%; > 25% staining) to 14 (22%; > 50% staining) with an increasing threshold of reactive cells. Similar shifts in the distribution of CK7 and CK20 reactivity occurred when different thresholds of reactivity were used for a positive result. There were no differences in CK7 or CK20 reactivity in pancreas only, ampulla only, and neoplasms involving both sites. Of 64 adenocarcinomas, 29 (45%) had no or single-cell CK17 reactivity, and 19 (30%) had reactivity in more than 50% of neoplastic cells. Ampulla of Vater and pancreas adenocarcinomas have similar CK immunophenotypes that cannot assist in distinguishing ampullary from pancreatic neoplasms on endoscopically procured tissue. CK17 staining occurs in approximately 50% of pancreaticobiliary adenocarcinomas and is usually patchy. Single antibody staining results, especially CK7 and CK20 coordinate reactivity, are influenced by the reactivity threshold used.

The utility of cytokeratin subsets in distinguishing Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma

AIMS

Accurate tumour classification is critical for meaningful epidemiological studies in the assessment of cancer incidence rates and trends. Differentiating primary gastric carcinoma from oesophageal carcinoma can be difficult, especially when tumours are large and involve both the oesophagus and stomach. Furthermore, adenocarcinomas of both organs typically are of intestinal histological type and arise in a background of intestinal metaplasia. Consequently, histological markers that reliably distinguish Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma would be useful. Cytokeratins (CK)7 and 20 are cytoplasmic structural proteins with restricted expression that help to determine the origin of many epithelial tumours including those of the gastrointestinal tract. The aim of this study was to determine the utility of co-ordinate CK7 and 20 expression in the distinction of Barrett's-related oesophageal adenocarcinoma from gastric adenocarcinoma arising in a background of intestinal metaplasia.

METHODS AND RESULTS

CK7 and 20 immunostaining was performed on randomly selected surgical resection specimens from patients with Barrett's-related oesophageal adenocarcinoma (n = 30) and intestinal type gastric adenocarcinoma (n = 14) arising in a background of intestinal metaplasia. A CK7+ CK20- immunophenotype was demonstrated in 27 of 30 (90%) patients with Barrett's-related oesophageal adenocarcinoma and only three of 14 (21%) gastric adenocarcinomas. The sensitivity, specificity and positive predictive value of a CK7+/20- immunophenotype for a diagnosis of Barrett's-related oesophageal adenocarcinoma was 90%, 79%, and 90%, respectively.

CONCLUSIONS

A CK7+/20- tumour immunophenotype is associated with Barrett's-related oesophageal adenocarcinoma and may be useful in accurate tumour classification, thus facilitating improving epidemiological evaluation of tumours at the oesophagogastric junction.

Diagnostic and prognostic tumor markers in the gastrointestinal tract

The gastrointestinal tract is the most common site of malignancies of any anatomic system in the body. An early detection of primary tumors of the bowel, pancreas, liver, stomach, and esophagus is often difficult in asymptomatic patients and for this reason these tumors are often detected at a relatively advanced stage, when symptoms lead to a diagnostic evaluation. Furthermore, gastrointestinal tract tumors have an extremely variable prognosis; thus, the identification of new prognostic parameters may be useful for selecting patients to more tailored therapies. In this work, the main molecular, genetic, tissular, and circulating tumor markers proposed for diagnosis and prognosis of gastrointestinal malignancies are reviewed and discussed.

Cytokeratins 8 and 19 in the mouse placental development

To investigate the expression and biological roles of cytokeratin 19 (K19) in development and in adult tissues, we inactivated the mouse K19 gene (Krt1-19) by inserting a bacterial beta-galactosidase gene (lacZ) by homologous recombination in embryonic stem cells, and established germ line mutant mice. Both heterozygous and homozygous mutant mice were viable, fertile, and appeared normal. By 7.5-8.0 days post coitum (dpc), heterozygous mutant embryos expressed lacZ in the notochordal plate and hindgut diverticulum, reflecting the fact that the notochord and the gut endoderm are derived from the axial mesoderm-originated cells. In the adult mutant, lacZ was expressed mainly in epithelial tissues. To investigate the possible functional cooperation and synergy between K19 and K8, we then constructed compound homozygous mutants, whose embryos died approximately 10 dpc. The lethality resulted from defects in the placenta where both K19 and K8 are normally expressed. As early as 9. 5 dpc, the compound mutant placenta had an excessive number of giant trophoblasts, but lacked proper labyrinthine trophoblast or spongiotrophoblast development, which apparently caused flooding of the maternal blood into the embryonic placenta. These results indicate that K19 and K8 cooperate in ensuring the normal development of placental tissues.

Cytokeratin immunoreactivity patterns in the diagnosis of short-segment Barrett's esophagus

BACKGROUND & AIMS

The origin of intestinal metaplasia in short segments of columnar mucosa at the esophagogastric junction has clinical importance but can be difficult to determine at endoscopy. Cytokeratin (CK) 7 and 20 patterns are specific for long-segment Barrett's esophagus; however, their utility in short-segment Barrett's esophagus has not been assessed.

METHODS

Endoscopic biopsy specimens from patients with long-segment Barrett's esophagus (n = 49), suspected short-segment Barrett's esophagus (n = 43), and gastric intestinal metaplasia (n = 26) were immunostained for CK7 and CK20. Comprehensive clinical data were obtained, including age, gender, and hiatal hernia and Helicobacter pylori status.

RESULTS

A Barrett's CK7/20 pattern was present in 48 (98%) of 49 patients with long-segment Barrett's esophagus, 35 (82%) of 43 with suspected short-segment Barrett's esophagus, and 0 (0%) of 26 patients with gastric intestinal metaplasia. Patients with suspected short-segment Barrett's esophagus with a Barrett's CK7/20 pattern were clinically similar to those with long-segment Barrett's esophagus. In contrast, patients with suspected short-segment Barrett's esophagus with no Barrett's CK7/20 pattern were clinically similar to those with gastric intestinal metaplasia.

CONCLUSIONS

A Barrett's CK7/20 pattern identifies a subset of patients with suspected short-segment Barrett's esophagus who have a patient profile similar to that seen in long-segment Barrett's esophagus. A Barrett's CK7/20 pattern is an objective marker of Barrett's mucosa that in conjunction with appropriate clinical and endoscopic data can be used by clinicians to better define patients with short-segment Barrett's esophagus.

Establishment and characterization of a new cell line derived from a human primary breast carcinoma

A new cell line, designated HDQ-P1, was successfully established from a primary ductal infiltrating mammary carcinoma by using a 3T3 feeder layer lethally irradiated to 60 Gy. The HDQ-P1 cells have been grown in culture for over 115 passages and have a doubling time of 60 hours. Characterization of the cell line was performed. This included morphology by light and transmission electron microscopy, karyotype, growth rate, telomerase expression, tumor antigen expression, xenograft implantation into nude mice, colony formation in soft agar, TP53 sequencing, and gene copy number of C-MYC, C-ERBB-2, and C-H-RAS oncogenes. The epithelial nature of this cell line was confirmed by ultrastructural analysis, expression of cytokeratins, and epithelial membrane antigen. The HDQ-P1 cells possess an extensively rearranged and polyploid karyotype, with an average of 20 recurrent marker chromosomes. Scatchard analysis demonstrated that both primary tumor and HDQ-P1 cells were estrogen- and progesterone-receptor negative. The HDQ-P1 cells had the same expression of human telomerase reverse transcriptase as other established breast cancer cell lines such as MDA-MB-231, SK-BR-3, and MCF-7. Direct DNA sequencing showed a point mutation which yielded to a stop codon at the amino acid 213 in exon 6 of the TP53 gene. A five-fold amplification of C-MYC was observed in HDQ-P1 cells. No amplification of C-ERBB-2 and C-H-RAS genes were observed. This cell line presents unique characteristics and may prove to be a good experimental model for investigating breast cancer biology.

Cytokeratin 7 and 20 expression in cholangiocarcinomas varies along the biliary tract but still differs from that in colorectal carcinoma metastasis

In the liver, the immunostaining of cytokeratins (CK) 7 and 20 has been used to distinguish usual peripheral cholangiocarcinomas (CC) and colorectal carcinoma metastasis (CRM). However, other subtypes of CC are not infrequent and may be particularly difficult to distinguish from CRM by histology and even immunohistochemistry. Therefore, 48 CC from different locations, either peripheral (n = 19), or nonperipheral, that is, from the large intrahepatic bile ducts, the hilum, and the extrahepatic bile ducts (n = 29), and with different cytoarchitectural patterns were tested for CK7 and CK20 and compared with 31 CRM. CC were positive for CK7 and CK20 in 96% and 70%, respectively, whatever the architecture and differentiation of the tumor. The labeling index (LI) of CK7 in CC was always high, whereas it was low or moderate for CK20. CK20-positive phenotype was significantly more frequent in nonperipheral than in peripheral CC (82% vs 47%; p = 0.007). CRM were all positive for CK20 with a high LI, and mostly negative (81%) for CK7. In conclusion, (1) the CK immunoprofile of CC varies according to the location of the tumor in the biliary tract, peripheral CC being more often CK7+/CK20-, and nonperipheral ones CK7+/CK20+; and (2) a decision tree based on CK20 LI and CK7 positivity allows the distinction of CRM and CC, even for the nonperipheral type.

Primary seminal vesicle carcinoma: an immunohistochemical analysis of four cases

Primary adenocarcinoma of the seminal vesicles is an extremely rare neoplasm. Because prompt diagnosis and treatment are associated with improved long-term survival, accurate recognition of this neoplasm is important, particularly when evaluating limited biopsy material. Immunohistochemistry can be used to rule out neoplasms that commonly invade the seminal vesicles, such as prostatic adenocarcinoma. Previous reports have shown that seminal vesicle adenocarcinoma (SVCA) is negative for prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PAP); however, little else is known of its immunophenotype. Consequently, we evaluated the utility of cancer antigen 125 (CA-125) and cytokeratin (CK) subsets 7 and 20 for distinguishing SVCA from other neoplasms that enter the differential diagnosis. Four cases of SVCA-three cases of bladder adenocarcinoma and a rare case of adenocarcinoma arising in a mullerian duct cyst-were immunostained for CA-125, CK7, and CK20. Three of four cases of SVCA were CA-125 positive and CK7 positive. All four cases were CK20 negative. All bladder adenocarcinomas and the mullerian duct cyst adenocarcinoma were CK7 positive and negative for CA-125 and CK20. In addition, CA-125 immunostaining was performed in neoplasms that commonly invade the seminal vesicles, including prostatic adenocarcinoma (n = 40), bladder transitional cell carcinoma (n = 32), and rectal adenocarcinoma (n = 10), and all were negative for this antigen. In conclusion, the present study has shown that the CK7-positive, CK20-negative, CA-125-positive, PSA/PAP-negative immunophenotype of papillary SVCA is unique and can be used in conjunction with histomorphology to distinguish it from other tumors that enter the differential diagnosis, including prostatic adenocarcinoma (CA-125 negative, PSA/PAP positive), bladder transitional cell carcinoma (CK20 positive, CA-125 negative), rectal adenocarcinoma (CA-125 negative, CK7 negative, CK20 positive), bladder adenocarcinoma (CA-125 negative), and adenocarcinoma arising in a mullerian duct cyst (CA-125 negative).

Detection and clinical relevance of micrometastatic cancer cells

The failure to reduce mortality of epithelial cancer patients is probably a result of the early dissemination of cancer cells to secondary sites, which is usually missed by conventional diagnostic procedures used for tumor staging. Individual carcinoma cells present in regional lymph nodes, blood, or distant organs (eg, bone marrow) can be detected by sensitive immunologic or molecular methods. Because the goal of adjuvant therapy is the eradication of occult micrometastatic tumor cells before metastatic disease becomes clinically evident, the early detection of micrometastases could identify those patients who might benefit from adjuvant therapy. In addition, more sensitive methods for detecting such cells should increase knowledge about the biologic mechanisms of metastasis, which might improve the diagnosis and treatment of micrometastatic disease. In this article, the recent developments in sensitive assays used for the detection of individual micrometastatic cancer cells in patients with epithelial tumors are reviewed.

Practical applications of immunohistochemistry in the diagnosis of soft tissue neoplasms

Immunohistochemistry is an extraordinarily powerful tool in the armamentarium of the diagnostic surgical pathologist. This article discusses some ways in which immunohistochemistry assists in the diagnosis of soft tissue neoplasms. Four common clinicopathologic scenarios in soft tissue pathology are presented and a practical approach to these rare neoplasms is discussed. The limitations of immunohistochemistry and possible future directions for the application of immunohistochemistry to sarcoma diagnosis are also reviewed.

Immunohistochemical characterization of pancreatic tumors induced by dimethylbenzanthracene in rats

Dimethylbenzanthracene (DMBA) induces pancreatic adenocarcinomas in rats 9 months after carcinogen exposure, with precursor lesions (tubular complexes) developing 1 month after initiation of treatment. Because previous studies have suggested an acinar cell of origin for these tumors, we investigated the expression pattern of ductal, acinar, and islet cell markers in these cancers to gain insight into their phenotype and cell of origin. Pancreatic neoplasms were induced in rats by implantation of DMBA into the head of the pancreas. Lesions studied included 10 early tubular complexes (DMBA for 2 weeks), 8 tubular complexes (DMBA for 1 month), and 10 adenocarcinomas (DMBA for 9 months). Normal rat pancreas served as a control. For comparison, 5 human ductal adenocarcinomas were also evaluated. Immunohistochemistry with ductal (keratin, cytokeratin 19, cytokeratin 20), acinar (chymotrypsin), and islet (chromogranin A) cell markers was performed to analyze the tissues. Rat tubular complexes and adenocarcinomas revealed strong expression of keratin, cytokeratin 19, and cytokeratin 20 in the cytoplasm of all neoplastic cells, absence of chymotrypsin, and rare immunoreactivity to chromogranin A. Human adenocarcinomas showed strong expression of keratin and cytokeratin 19 in all neoplastic cells, expression of cytokeratin 20 in 5-20% of cells, and absence of chymotrypsin and chromogranin A. Pancreatic adenocarcinomas induced by DMBA in rats express markers consistent with a ductal phenotype, as observed in human tumors. Ductal marker expression in early tumor stages suggests a ductal cell of origin.

The limited difference between keratin patterns of squamous cell carcinomas and adenocarcinomas is explicable by both cell lineage and state of differentiation of tumour cells

AIM

To study the differentiation of epithelial tissues within their histological context, and to identify hypothetically, on the basis of keratin pattern, the putative tissue origin of a (metastatic) carcinoma.

METHODS

Using well characterised monoclonal antibodies against individual keratins 7, 8, 18, and 19, which are predominantly found in columnar epithelia, and keratins 4, 10, 13, and 14, predominantly expressed in (non)-keratinising squamous epithelia, the keratin patterns for a series of 45 squamous cell carcinomas and 44 adenocarcinomas originating from various epithelial tissues were characterised.

RESULTS

The predominant keratins in all adenocarcinomas proved to be 8, 18, and 19. In addition, these keratins were also abundantly present in squamous cell carcinomas of the lung, cervix, and rectum and, to a lesser extent, of the larynx, oesophagus, and tongue, but not in those of the vulva and skin. Keratins 4, 10, 13, and 14 were present in almost all squamous cell carcinomas, but also focally in some of the adenocarcinomas studied.

CONCLUSIONS

There is a limited differential expression of distinctive keratin filaments between squamous cell carcinomas and adenocarcinomas. Apparently, squamous cell carcinomas that originate from columnar epithelium by squamous metaplasia gain the keratins of squamous cells but retain the keratins of columnar epithelial cells. However, the simultaneous expression of two of three squamous keratins (4, 10, and 13) identifies a squamous cell carcinoma, and thus might be useful in solving differential diagnostic problems.

Effects of fractionated irradiation on the cytoskeleton and basal lamina in parotid glands--an immunohistochemical study

Cytoskeletal, cytocontractile and basement membrane proteins were studied using the immunofluorescence technique in the parotid gland in female rats after half-side fractionated megavoltage irradiation. The non-irradiated parallel-handled parotid glands served as controls. The qualitative expression of cytoskeletal proteins remained unchanged 10 days following irradiation compared to controls, i.e. cytokeratin was observed but not vimentin, desmin or GFAP (glial fibrillary acidic proteins). Six months after irradiation the cytokeratin expression adjacent to duct lumina was clearly stronger. Actin staining was more pronounced in the periphery of the acini. Ten days after irradiation no alterations of the basal lamina proteins, laminin and fibronectin, were detected. Six months post-irradiation laminin deposits were detected in areas where the entire acini had degenerated and had been replaced by fibrosis. An increased expression of fibronectin was also observed in the stroma at that time, reflecting an increased fibrosis. In areas where the acini remained, laminin immunofluorescence was mainly found in basal laminae of normal thickness, but the mean diameter of the acini seemed to have increased. This indicates a regeneration of acini and a restructuring of the basal lamina of the parenchyma.

Cytokeratin 14 as a marker of squamous differentiation in transitional cell carcinomas

The presence of squamous differentiation in transitional cell carcinomas has been variably related to prognosis and response to radiotherapy. This study sought to establish whether cytokeratin (CK) 14, normally expressed in the basal cells of squamous epithelium, could be used as a reliable marker of the emergence of a squamous phenotype in transitional cell carcinomas. In a series of 42 tumours, CK14 was expressed in areas of squamous morphology, whereas CK20 identified continuing urothelial differentiation. Furthermore, focal positivity for CK14 was present in a proportion of tumours with no morphological evidence of squamous differentiation, suggesting that it is a more sensitive marker of phenotypic switch. Investigation of CK subtypes may be more powerful than morphology alone in clinical studies of transitional cell carcinomas as CK expression profiles have been related to treatment response in other tumour types.

Establishment and characterization of two new cell lines derived from human metastatic breast carcinomas

Two human cancer cell lines (MA 2 and MA 3) were established from pleural effusions of infiltrating ductal carcinomas of the breast. The lines were maintained in continuous monolayer culture with doubling times of 70 (MA 2) and 78 (MA 3) hr for more than two years and possessed extensively rearranged abnormal karyo-types with modal chromosome number of 83 (MA 2) and 81 (MA 3) and DNA index values of 1.65 and 1.77, respectively. No amplifications or rearrangements were evident in the c-myc, int-2, c-erb B2, c-Ha-ras, or hst 1 genes in MA 2 and MA 3 cell lines. The clinical histories of the patients from whom the cell lines were derived are reported and compared with the results observed in the cell lines in vitro. The presence of CEA, CA 15-3, and MCA tumor markers observed in the primary tumor tissues was retained by the established cell lines. While the primary tumor tissues were ER+/PgR borderline+ (MA 2) and ER-/PgR+ (MA 3), the MA 2 line was ER+/PgR- and the MA 3 line remained ER-/PgR+. The MDR P-glycoprotein was not expressed either in primary tumor tissues or in the respective cell lines. High expression of cytokeratins 7, 18, and 19 was evident by immunohistochemical analysis in each cell line. whereas cytokeratins 8 and 17 were poorly or not at all expressed. The treatment history of the patients from whom the cell lines were derived involved CMF followed six months later by novantrone and cisplatin plus VP 16 (MA 2) and FEC followed four years later by CMF (MA 3). The chemosensitivity pattern assay of the cell lines indicated that the MA 2 line was sensitive to doxorubicin, cisplatin, and vinblastine, whereas the MA 3 line was sensitive to doxorubicin and cisplatin. The characteristics of these cell lines indicate them to be a good experimental model to investigate breast cancer biology and anticancer drug response.

The prognostic application of cytokeratin typing of nonsmall cell lung carcinoma. A retrospective study

BACKGROUND

In a previous study, the authors used a variety of anticytokeratin monoclonal antibodies to show that a large proportion of lung tumors cytologically diagnosed as squamous cell carcinoma contain cells expressing simple epithelial cytokeratins, suggesting that these tumors have their origin in adenocarcinoma. These findings raised the possibility that cytokeratin (CK) typing might have a diagnostic capacity not attainable by standard histopathology. The aim of the current study was to assess the value of CK typing for this purpose by determining the correlation between the diagnosis of lung tumors based on CK typing and the survival rate of the patients.

METHODS

Paraffin embedded tissue sections of 66 nonsmall cell lung carcinoma (NSCLC) specimens were examined. These included 18 adenocarcinomas, 32 squamous cell carcinomas, and 16 undifferentiated carcinomas, all diagnosed surgically and histopathologically, and further classified as either Stage I or II. CK typing was performed using the streptavidin-biotin-peroxidase method, employing the following anti-CK monoclonal antibodies: Ks.B.17 (which reacts with CK 18), A3-3 (which reacts with CK 13), and E5-9 (which reacts with CK 10).

RESULTS

Comparison between the 5-year survival rates (5 ysr) of patients with different NSCLC indicated that all types of Stage II tumors had a much poorer prognosis than Stage I tumors. Differences found in the 5 ysr among patients with different types of Stage I tumors were not statistically significant (adenocarcinomas, 33% 5 ysr; squamous cell carcinomas, 59% 5 ysr; undifferentiated carcinomas, 36% 5 ysr; all diagnosed by conventional histopathology). Similarly, no significant differences were noted in 5 ysr between patients with tumors stained positively or negatively with monoclonal antibodies A3-3 or E5-9 (anti-CK 13 and anti-CK 10, respectively). In contrast, highly significant differences (P = 0.002) were found in the 5 ysr between patients with Stage I tumors positively or negatively stained with monoclonal antibody Ks.B.17 (23% vs. 75% 5 ysr, respectively) regardless of the histologic types of tumors. Especially informative was a combination of immunohistochemical and histologic diagnoses, with best survival rates (87% 5 ysr) in Ks.B.17 negative tumors histologically diagnosed as Stage I squamous cell carcinomas and worst survival rates (14% 5 ysr) in Ks.B.17 positive tumors diagnosed as adenocarcinomas.

CONCLUSIONS

The current study showed that CK 18 typing of lung tumors can provide a more accurate diagnosis and therefore facilitate the planning of more suitable therapeutic approaches.

Oncogenic regulation and function of keratins 8 and 18

Keratin 8 (K8) and keratin 18 (K18) are the most common and characteristic members of the large intermediate filament gene family expressed in 'simple' or single layer epithelial tissues of the body. Their persistent expression in tumor cells derived from these epithelia has led to the wide spread use of keratin monoclonal antibodies as aids in the detection and identification of carcinomas. Oncogenes which activate ras signal transduction pathways stimulate expression of the K18 gene through transcription factors including members of the AP-1 (jun and fos) and ETS families. The persistent expression of K8 and K18 may reflect the integrated transcriptional activation of such transcription factors and, in the cases of ectopic expression, an escape from the suppressive epigenetic mechanisms of DNA methylation and chromatin condensation. Comparison of the mechanisms of transcriptional control of K18 expression with expression patterns documented in both normal and pathological conditions leads to the proposal that persistent K8 and K18 expression is a reflection of the action of multiple different oncogenes converging on the nucleus through a limited number of transcription factors to then influence the expression of a large number of genes including these keratins. Furthermore, correlation of various tumor cell characteristics including invasive behavior and drug sensitivity with K8 and K18 expression has stimulated consideration of the possible functions of these proteins in both normal development and in tumorigenesis. Recent developments in the analysis of the functions of these intermediate filament proteins provide new insights into diverse functions influenced by K8 and K18.

Differential responsiveness of proliferation and cytokeratin release to stripped serum and oestrogen in the human breast cancer cell line, MCF-7

In vitro research into hormone sensitivity and the relation to proliferation of cytokeratin release from cancer cells is scarce. Therefore, we examined the stimulation of proliferation and the release of cytokeratins in a breast cancer cell culture model. Cell growth was stimulated by 17 beta-oestradiol (10(-11) M), stripped serum (10%) and by the two together. Cytokeratin release was stimulated only by stripped serum, oestradiol having no effect. After long incubation periods (> 12 h), cytokeratin release also commenced in the control and oestradiol treatments. Release rate versus time analysis suggested that there are two different release processes. Cytokeratin release was first stimulated at a stripped serum concentration approximately 100 times lower than that which initiated proliferation. Pharmacological alteration of proliferation with cordyceptin resulted in growth changes without alterations in cytokeratin release. We conclude that cytokeratin release in these cells is unrelated to proliferation, independent of oestrogen action and probably in some way related to growth factor receptor function.