Allele-specific loss in chromosome 9p loci in preneoplastic lesions accompanying non-small-cell lung cancers

BACKGROUND

Carcinogenesis is a multistep process, which may begin as a consequence of chromosomal changes. Deletions in the short arm of chromosome 9 (9p) have been observed in lung carcinomas. In addition, morphologically recognizable preneoplastic lesions, frequently multiple in number, precede onset of invasive carcinomas.

PURPOSE

We tested for deletions and loss of heterozygosity (LOH) at 9p loci in preneoplastic and neoplastic foci in lungs of patients with non-small-cell lung carcinomas (NSCLCs).

METHODS

Seven archival, paraffin-embedded, surgically resected NSCLC specimens were selected. They were predominantly from patients with adenocarcinomas and contained multiple preneoplastic lesions, including hyperplasia, metaplasia, dysplasia, and carcinoma in situ (CIS). Fifty-three histologically identified preneoplastic and malignant lesions present in bronchi, bronchioles, and alveoli were precisely microdissected from stained tissue sections with a micromanipulator. Stromal lymphocytes were used to determine constitutional heterozygosity. The specimens were analyzed for LOH using polymerase chain reaction-based assays for polymorphism in dinucleotide repeats (microsatellite markers) in interferon alfa (IFNA) and D9S171 loci on 9p.

RESULTS

All seven cases were constitutionally heterozygous for one or both microsatellite markers. Five of seven cases had LOH at one or both 9p loci in the invasive primary cancers (doubly informative cases). Four of these five cases also revealed LOH in preneoplastic foci. In the doubly informative cases, LOH was detected in five (38%) of 13 foci of hyperplasia, four (80%) of five foci of dysplasia, and three (100%) of three CIS lesions. LOH was detected in preneoplastic lesions from all regions of the respiratory tract, including bronchi, bronchioles, and alveoli, and involved five different cell types. The identical allele was lost from both the preneoplastic lesions and the corresponding tumors (12 of 12 lesions, 17 of 17 comparisons), a phenomenon we have referred to as "allele-specific mutation." Statistical analyses employing a cumulative binomial test demonstrated that the probabilities of such findings occurring by chance are 2.4 x 10(-4) and 7.6 x 10(-6), respectively. From comparisons with the previously published data on other chromosomal abnormalities in the same tissue specimens, it appears that LOH at 3p and 9p loci occurred early in the hyperplasia stage, but the ras gene point mutations were relatively late, at the CIS stage.

CONCLUSIONS

LOH at 9p loci occurs at the earliest stage in the pathogenesis of lung cancer and involves all regions of the respiratory tract. LOH in NSCLC is not random but targets a specific allele in individuals. Studying preneoplastic lesions may help identify intermediate markers for risk assessment and chemoprevention.

[Expression of CD44 alternative splicing variants in lung cancer]

Expression of isoforms of the CD44 is generated by alternative splicing of CD44 gene; CD44H: lacks all 10 alternative exons, CD44R: the alternative exons v8 to v10, CD44V: other group of variants which contains the alternative exon v6. In some tumors such as colorectal cancer, breast cancer, non-Hodgkin lymphoma, and melanoma, over-expressed CD44 isoform which contains such alternative-spliced variant exons may play a causative role in tumor metastasis. In lung cancer, however, the role of CD44 variants in tumor progression and metastasis is uncertain. In our study and reported literature, no definite correlation was observed between the expression of specific CD44 isoform and tumor progression or metastasis of lung cancer.

Allele-specific mutations involved in the pathogenesis of endemic gallbladder carcinoma in Chile

Although gallbladder carcinoma is one of the most frequent neoplasms in Chile, there is limited information about the molecular changes involved in its pathogenesis. We investigated the incidence of ras gene mutations and loss of heterozygosity (LOH) at the following genes/loci: p53, DCC, rb, 5q 3p, 8p, and 9p. We precisely microdissected 194 relevant areas from paraffin-embedded microslides from 25 gallbladder carcinomas and their accompanying nonneoplastic lesions (which were present in 15 cases) from patients in Chile. The specimens were analyzed by PCR-based assays for LOH, and we designed a RFLP method for ras mutations and immunohistochemistry for p53 protein overexpression. We determined that LOH at p53 (91%), 9p (50%), 8p (44%) and DCC (31%) are frequent events and that LOH at p53, 9p, and DCC are early events, while ras mutations and LOH at 3p, rb, and 5q occurred occasionally. LOH at p53 occurred more frequently and earlier than protein overexpression. The mean number of mutations present in invasive carcinomas was 2.1, and in six cases, LOH at the p53 gene was the sole mutation detected. The same allele was lost in 61 (93%) of 71 nonneoplastic foci as in the corresponding invasive carcinomas for all four mutations studied. The odds of this occurring by chance are approximately 4 x 10(-15). Although clonality cannot be excluded, allelic loss appears to be highly directed, but the mechanism for allele-specific mutations remains to be determined.

Frequent loss of the short arm of chromosome 9 in resected non-small-cell lung cancers from Japanese patients and its association with squamous cell carcinoma

We analyzed 87 Japanese non-small-cell lung carcinomas (NSCLC) including 30 squamous cell, 51 adenocarcinomas and 6 large-cell carcinomas for loss of heterozygosity (LOH) on the short arm of chromosome 9, and we correlated our findings with clinicopathological features. We used four polymorphic microsatellite markers on 9p (interferon A gene, D9S171, D9S126, and D9S169), which flank the critical region (9p21-22) involved in lung cancer. We observed alterations of DNA sequences at 9p in NSCLC (27 of 82 informative cases or 33%). Concordance among the four markers was high (87%), indicating that the deletions often were relatively large. The 27 genetic alterations observed on 9p include 26 examples of LOH, 1 homozygous deletion, and 1 case with LOH and evidence of microsatellite alteration characterized by shift in band mobility. We noted a high frequency of LOH at 9p especially in squamous cell carcinoma (17 of 29 informative cases or 59%), and in poorly differentiated NSCLC (12 of 23 informative cases or 52%). There was no correlation between LOH at 9p and the other clinical parameters, including survival, gender, tumor size and the presence of regional or distant metastases. In contrast to other reports, we found only rare instances of homozygous deletions (1%) and microsatellite alteration showed as a mobility shift (1%). Our findings demonstrate that LOH at the short arm of chromosome 9 is correlated with squamous cell and poorly differentiated carcinomas in Japanese patients with NSCLC.

Neurogenic tumors of the mediastinum originated from the vagus nerve

Thirty-nine patients with neurogenic tumors observed between 1974 to 1992 were reviewed. There were 32 patients with neurilemoma, one with neurofibroma, five with ganglioneuroma, and one with malignant neurilemoma. Two cases of neurilemoma originated from the vagus nerve, which is very rare. Surgical resection is recommended, not only to confirm the nature of the lesion, but also to prevent further growth and compression on adjacent structures. For benign encapsulated neurogenic tumors, resection is curative.

Allele-specific chromosome 3p deletions occur at an early stage in the pathogenesis of lung carcinoma

BACKGROUND

Deletions in the short arm of chromosome 3 (3p) are present in most lung carcinomas.

OBJECTIVE

To investigate the role of these chromosome 3p deletions in the pathogenesis of non-small cell lung carcinomas.

DESIGN

Seven archival, paraffin-embedded, surgically resected lung cancer specimens were studied. Fifty precisely identified malignant and preneoplastic lesions present in bronchi, bronchioles, and alveoli were microdissected from stained slides and analyzed for allele loss using polymerase chain reaction-based assays for dinucleotide repeat polymorphisms at three chromosome 3p loci (3p14, 3p21.3, and 3p25).

SETTING

University-based medical center and affiliated hospitals.

SUBJECTS

Samples were analyzed from seven patients who underwent surgical resection with curative intent for non-small cell lung cancer and whose specimens included extensive multifocal areas of preneoplastic lesions (hyperplasia, metaplasia, dysplasia, or noninvasive cancer).

RESULTS

Lymphocytes from all seven cases were heterozygous (ie, informative) for all three microsatellites analyzed. Six (86%) of seven invasive cancers had loss of heterozygosity at one or more chromosome 3p sites. In the accompanying preneoplastic lesions, loss of heterozygosity was detected in none of two normal bronchioles, 13 (76%) of 17 hyperplasias, six (86%) of seven dysplasias, and four (100%) of four noninvasive cancers. Loss of heterozygosity was detected throughout the respiratory tract, in bronchi, bronchioles, and alveoli. In 18 (78%) of 23 preneoplastic lesions, the specific alleles lost were identical to those lost in the corresponding carcinomas. The probability of this happening by chance is 5.3 x 10(-3).

CONCLUSIONS

Deletions in the short arm of chromosome 3 occur at the earliest stage (hyperplasia) in the pathogenesis of lung cancer and involve all regions of the respiratory tract. Allele loss is highly specific, but its mechanism remains unknown. Our findings may be of considerable biologic, prognostic, and clinical significance.

The relationship between the immunodetection of transforming growth factor-beta in lung adenocarcinoma and longer survival rates

We immunohistochemically examined the expression of transforming growth factor-beta (TGF-beta) on tissue specimens from primary 124 human lung adenocarcinoma, using a polyclonal antibody. The overall mean immunoreactivity of TGF-beta was 25.7 +/- 22.9, therefore we separated patients into two groups according to their mean immunoreactivity. There were 59 (48%) with a high TGF-beta and 65 (52%) with a low TGF-beta. No correlation was observed between the expression of TGF-beta and clinicopathological factors except for degree of differentiation. The 5-year survival rates of patients with high and low TGF-beta were 71% and 37%, respectively (P < 0.05). A multivariate analysis using the Cox life table regression model showed TGF-beta to be a significantly independent factor. We thus concluded, based on our findings, that the expression of TGF-beta was found to be related to a better prognosis. Therefore, estimating the negative cell proliferation activity induced by TGF-beta on immunohistochemical technique is considered to be useful for determining the patients' prognosis in cases of lung adenocarcinoma.

Glutathione S transferase Pi is a powerful indicator in chemotherapy of human lung squamous-cell carcinoma

We immunohistochemically investigated the expression of glutathione S transferase pi (GST- pi) and clarified the correlation between GST-pi and the results of chemosensitivity testing on the tissue of primary human squamous-cell carcinoma of the lung. The expression of GST-pi was evaluated in 105 cases and their level of chemosensitivity was estimated by the in vitro succinate dehydrogenase inhibition test for cisplatin, Adriamycin, cyclophosphamide, mitomycin C, vindesine and fluorouracil. Tumors in which 25% and more of the cells stained for GST-pi were classified as having a high GST-pi expression, while those tumors demonstrating less than 25% of the cells staining for GST-pi were considered to have a low expression GST-pi. The percentage of high GST-pi was 52% (53 of 105) while that of low GST-pi was 48% (52 of 105). No significant correlation between the expression of GST-pi and clinicopathologic factors was observed, while no significant difference in the survival of the two groups was found either. An increase in succinate dehydrogenase activity was recognized in the high-GST-pi group compared with the low-GST-pi group for each anticancer drug; however, no statistical significance was seen except for cisplatin. In the cases with adjuvant combination chemotherapy using cisplatin after a complete resection, all cases demonstrating a relapse were associated with a high GST-pi. These findings thus indicate that an overexpression of GST-pi is related to the resistance to cisplatin in human lung squamous-cell carcinoma. It is therefore important to select carefully the optimal anticancer drug for high-GST-pi cases.

p53 nuclear immunostaining and gene mutations in non-small-cell lung cancer and their effects on patient survival

BACKGROUND

p53 gene mutations are known to occur in about half of all non-small-cell lung cancer (NSCLC) cases. Mutations of the p53 gene usually but not always lead to an increased half life of the p53 protein, and result in a nuclear accumulation of protein which can be detected by immunohistochemistry (IHC). Controversy still exists as to whether the presence of an aberration of the p53 gene or protein is a poor prognostic indicator in patients with NSCLC.

PATIENTS AND METHODS

DNA samples and paraffin blocks were obtained from 129 patients of 143 consecutive patients who underwent a pulmonary resection during a 22-month period from July 1991 to April 1993. Mutations of the p53 gene occurring at exons 5-8 were detected by a polymerase chain reaction (PCR)/single strand conformation polymorphism (SSCP) assay, while the nuclear accumulation of the p53 protein was detected by immunohistochemistry.

RESULTS

Of the patients studied, 35% had mutations and 54% showed overexpression, when we defined a positive case as being one in which more than 10% of the tumor cell nuclei were stained. There was a 59.5% concordance between the p53 gene mutations and p53 immunopositivity. p53 immunopositivity in adenocarcinoma and any p53 abnormality (i.e. p53 immunopositivity and/or mutation) in adenocarcinoma were a poor prognostic indicator. However, Cox's proportional hazards model indicated that the stage was the only significant prognostic factor.

CONCLUSIONS

p53 immunopositivity and mutations of the p53 gene are frequently seen in NSCLC. They are considered to be mutually related but may sometimes represent a different aspect of p53 abnormality. p53 alteration may be a poor prognostic indicator only in a subset of patients with NSCLC, especially for adenocarcinoma.

Cathepsin B expression and laminin degradation as factors influencing prognosis of surgically treated patients with lung adenocarcinoma

We examined, immunohistochemically, tissues from primary lung adenocarcinomas. In 142 tumors, the mean overall labeling percentage of cathepsin B was 26.5 +/- 22.3 (SD). The mean labeling percentage of cathepsin B in cases with stage I disease was lower than that in cases with stages IIIA, IIIB, or IV disease (P < 0.05). Of the 115 tumors examined for laminin-positive basement membranes, 54 (47%) had a continuous pattern and 61 (53%) had a discontinuous pattern. The mean labeling percentage of cathepsin B was 35.0 +/- 24.2 in tumors with a discontinuous pattern, compared with the 21.9 +/- 16.9 in those with a continuous pattern (P < 0.01). The overall 5-year survival rates of patients with high and low cathepsin B expressions were 26% and 77%, respectively (P < 0.01), including 45% and 94% for patients with stage I disease, respectively (P < 0.01), and 15% and 60% for those with stage IIIB disease, respectively (P < 0.05). Multivariate analysis using the Cox life table regression model showed cathepsin B to be a significantly independent factor associated with death due to the disease. We conclude from this study that tumors with a discontinuous pattern of laminin have a higher percentage of cathepsin B, and the survival rate was poor for patients with a high expression of cathepsin B. Thus, cathepsin B may be useful in assessing prognosis in lung adenocarcinoma.

K-ras mutations are a relatively late event in the pathogenesis of lung carcinomas

We investigated preneoplastic lesions associated with lung cancer to determine at what stage in lung carcinogenesis K-ras mutations appear. We selected six archival lung cancer resection cases that had ras mutations. We precisely microdissected 74 relevant areas from paraffin-embedded sections. K-ras mutations at codons 12, 13, and 61 were determined by the designed restriction fragment length polymorphism method using mismatched nested primers and confirmed by direct sequencing. All samples of invasive and metastatic cancers had K-ras mutations, as did four of five lesions of noninvasive cancer. Mutations were detected in only 1 of 12 dysplastic lesions and were absent from hyperplastic and normal-appearing cells. In all cases, the specific point mutations and the mutational pattern in the tumors, metastases, and the corresponding noninvasive lesions were identical. These results indicate that K-ras mutations arise relatively late in the pathogenesis of lung cancer and may be associated with the appearance of the malignant phenotype.

Video thoracoscopic excision of an intercostal neurilemoma presenting as a lateral chest wall tumor

Thoracoscopic surgery has expanded with advances in endoscopic surgical instrumentation. We report on a 21-year-old woman with a complete thoracoscopic resection of an intercostal neurilemoma, which occurred extrapleurally in the ninth intercostal space of the lateral thoracic wall. The tumor was 70 x 40 x 25 mm in size, but a thoracotomy with a rib resection was avoided. The patient had an uncomplicated postoperative course and was discharged on the fourth postoperative day. Thoracoscopic resection of an intercostal neurilemoma, presenting as a lateral chest wall tumor, may be a safe and useful approach with an improved cosmetic result.

[Experience with atrioventricular valve replacement in infants and children]

From 1980 to 1989, nine infants and children underwent valve replacement. These replacements consisted of seven mitral valve replacement (MVR), one left atrioventricular valve replacement, and one aortic valve (AVR) replacement. We excluded AVR from this report. Follow-up period of 8 cases were 68 months in an average. During this period, 2 cases were not thought to be satisfactory as antithrombotic therapy, in which one revealed malfunctioning prosthesis, and secondary MVR implantation was performed. Another one is free from any complications. We experienced the difficulty of antithrombotic therapy following valve replacement in infants and children. It is supposed that combined use of anticoagulant therapy agent and antiplatelet agent may be necessary as antithrombotic therapy, especially in childhood.

Neoadjuvant chemotherapy in patients with small-cell lung-cancer - radiographic and clinicopathological analysis

A comparative study on the effect of neoadjuvant chemotherapy was performed for small cell lung cancer, by radiographic and histopathological examinations. Four patients with small cell lung cancer were preoperatively treated with the combination of cyclophosphamide, doxorubicin, vincristine, nimustine, cisplatin and vindesine, for 2 to 3 cycles. The clinical responses to the neoadjuvant chemotherapy included 2 complete, one partial response and one no change. All four patients underwent a planned operation. Based on microscopical evidence, the two complete responders had a residual tumor in the resected specimens. One was tumor-free after 28 months, while the other succumbed to operation-related death at 2 months. The remaining two inadequate responders relapsed and died shortly following operation. We believe a clinically complete responder should be differentiated from a 'true' complete responder by histopathological examination.

Different site mutation of the K-ras gene in a patient with metachronous double lung cancers

We present a case with metachronous double lung cancers proved by molecular analysis. A male patient first had lung cancer discovered when he was 67 years old, and a second lung cancer was found when he was 71 years old. Pathologically, the first cancer was moderately to well differentiated adenocarcinoma and the second cancer was well differentiated adenocarcinoma. These findings suggested that the second cancer was not metastasis from the first lung cancer but a second primary lung cancer. According to the PCR and oligonucleotide mutation specific dot blot hybridization, the first lung cancer had a GGT to GTT mutation, while the second lung cancer had a GGT to TGT mutation at codon 12 of the K-ras gene. These results thus prove that these tumors were metachronous double cancers.

Proliferating cell nuclear antigen expression and argyrophilic nucleolar organizer regions as factors influencing prognosis of surgically treated lung cancer patients

Cell proliferation in 211 primary non-small cell lung carcinomas was assessed by using an immunostaining of proliferating cell nuclear antigen (PCNA) and a silver staining of argyrophilic nucleolar organizer region (Ag-NOR). More than 5% PCNA positive cells was designated PCNA(+), and less than 5% was PCNA(-). A mean number or more of the Ag-NOR was a high Ag-NOR count, and less than the mean number was a low Ag-NOR count. The proportion of the tumors with PCNA(+) and high Ag-NOR counts showed an increase in patients in an advanced stage of the disease (P < 0.05). In 125 patients with stage I disease, the 5-year survival rate was 20% in patients with PCNA(+) and high Ag-NOR counts, compared with 47% in those with either PCNA(+) or high Ag-NOR counts and 76% in those with PCNA(-) and low Ag-NOR counts (P < 0.05). Our data suggest that the tumors with PCNA(+) and high Ag-NOR counts have a high proliferative activity. The combination analysis of PCNA and Ag-NOR may be useful in assessing prognosis in lung cancer, even in stage I disease.

Mediastinal tumor and application of thoracoscopic surgery

Thoracoscopic resection of a mediastinal tumor or cyst was done in three patients: two with neurogenic tumors and one with a bronchogenic cyst. The tumors and cyst showed evidence of a discrete plane on computed tomography of the chest. The mean operation time and estimated blood loss were 156 min and 45 g, respectively. For all three patients, the chest drain was removed within 48 h after operation, and there were no complications related to thoracoscopic surgery. The advantages of this approach are less pain, early return to normal activity, and an acceptable cosmetic appearance. Based on our experience, thoracoscopic surgery is considered the treatment of choice for certain mediastinal tumors or cyst.

The mutation of codon 249 in the p53 gene is not specific in Japanese hepatocellular carcinoma

Hepatocellular carcinoma samples obtained from 59 patients at surgical resection were examined for mutations of the third base at codon 249 of the p53 gene, using the polymerase chain reaction and oligonucleotide hybridization techniques. This point mutation, which is frequently observed in HCC cases from Southern Africa and Quidong in China, was not recognized in either 60 hepatocellular carcinomas or 53 noncancerous liver tissue samples from Japan. Thirty-four of 45 patients (75.6%) were positive for the hepatitis C virus, which was a higher rate than that for hepatitis B virus infection (9 of 55; 16.4%). The exposure to aflatoxin B1 was not considered to be remarkable. These results suggest that the point mutation of the third base at codon 249 is not common in Japanese patients, and it is suggested that numerous other factors affect the mutation of the p53 gene and the development of hepatocellular carcinoma.

Monoclonal antibody KP16D3 as a prognostic marker in stage I lung adenocarcinoma

Monoclonal antibody KP16D3 recognizes a 60 kDa protein associated with mucin-nonproducing papillary adenocarcinoma, especially that originating from nonciliated bronchiolar epithelial cells of the lung. We immunohistochemically examined 56 primary lung adenocarcinomas using the monoclonal antibody KP16D3. Of these tumors, 31 (55%) were positive for KP16D3 immunoreactivity. The disease-free survival rates showed no statistical differences between KP16D3-positive and KP16D3-negative patients. However, in stage I and T1 disease, the disease-free survival rates of KP16D3-positive patients were statistically lower than those of KP16D3-negative patients (P < 0.05). These findings suggest that KP16D3 may be useful as a prognostic marker for patients with stage I primary lung adenocarcinoma. Conversely, use of this marker and subtyping of lung adenocarcinomas reflect the prognosis of the disease.

[A case of a traumatic diaphragmatic true hernia manifesting itself 12 years after the accident]

A case of surgical treatment of a traumatic diaphragmatic true hernia was presented, which manifested itself as symptoms of left chest oppression 12 years after the accident. The patient was a 66-year-old woman, who met traffic accident in 1976. She was first pointed out abnormal shadow on the chest X-ray in 1981 and began to feel chest oppression in 1988. Barium examination of the upper gastrointestinal tract and chest CT scan revealed a part of corpus ventriculi and colon herniated into the left hemithorax. Diaphragmatic hernia was diagnosed and the operation was performed through the thoracic approach in June 1991. The diaphragm was found to have a hernia sac and a defect at the central tendon. The hernia sac containing the stomach and colon was opened to reduce it's contents into the abdominal cavity. The defect was closed by mattress suture with pledgets and continuous over and over suture. The patient ran a favorable post operative course. A true type among traumatic diaphragmatic hernia is a very rare case in the literature.

Sarcoid reactions in regional lymph nodes of primary lung cancer

A 66-year-old woman diagnosed as having primary lung cancer with an enlargement of the mediastinal, subcarinal and bilateral hilar lymph nodes underwent a thoracotomy after preoperative chemotherapy. The histological examination showed a moderately differentiated papillary adenocarcinoma in the left upper lobe without any metastases to the regional lymph nodes; however, non-caseous epithelioid granulomas without necrosis were observed in the nodes. These changes were considered to be sarcoid reactions, since no other physiological and laboratory findings compatible with systemic sarcoidosis were observed. The histological findings suggested the possibility that the regional lymph nodes were not involved with the tumor cells at the time of lung cancer diagnosis. Despite the rarity of this condition, sarcoid reactions in the regional lymph nodes must be kept in mind when an enlargement of bilateral hilar lymph nodes is detected in patients with lung cancer, and a good prognosis may be expected in cases with sarcoid reactions in the regional lymph nodes.

Early squamous lung cancer and longer survival rates

The criteria for early squamous lung cancer remain open to discussion as patients who have been treated for early stage lung cancer, such as T1N0M0, and appear to have been cured clinically may die from recurrent or metastatic tumors. We reviewed the pathological data on 242 surgical patients with squamous lung cancer and found 31 cases (13%) of early lung cancer, included were early lung cancer of the hilar type as a lesion restricted to the bronchial wall without lymph node involvement, and early lung cancer of the peripheral type as a lesion of less than 2 cm and surrounded by visceral pleura but without lymph node involvement. Of 89 patients with hilar-type squamous lung cancer, 17 (19%) had early lung cancer, and 14 (9%) of 153 patients with peripheral-type squamous lung cancer had early lung cancer (p < 0.05). For early lung cancer of the hilar type, all but 1 (94%) were detected using sputum cytologic study and bronchoscopy. For early lung cancer of the peripheral type, all were detected on chest X-ray, but 57% were cytologically proven to be malignant. The 5-year survival rate for patients with early lung cancer, according to this new criteria is 90%; 92% for the hilar type and 88% for the peripheral type. Thus, classification of early squamous lung cancer is pertinent for determining the prognosis and selection of treatment. We emphasize that efforts be made to detect early lung cancer.