Dermoscopic diagnosis by a trained clinician vs. a clinician with minimal dermoscopy training vs. computer-aided diagnosis of 341 pigmented skin lesions: a comparative study

BACKGROUND

In the last few years digital dermoscopy has been introduced as an additional tool to improve the clinical diagnosis of pigmented skin lesions.

OBJECTIVE

To evaluate the validity of digital dermoscopy by comparing the diagnoses of a dermatologist experienced in dermoscopy (5 years of experience) with those of a clinician with minimal training in this field, and then comparing these results with those obtained using computer-aided diagnoses.

METHODS

Three hundred and forty-one pigmented melanocytic and non-melanocytic skin lesions were included. All lesions were surgically excised and histopathologically examined. Digital dermoscopic images of all lesions were framed and analysed using software based on a trained artificial neural network. Cohen's kappa statistic was calculated to assess the validity with regard to the correct diagnoses of melanoma and non-melanoma.

RESULTS

Sensitivity was high for the experienced dermatologist and the computer (92%) and lower for the inexperienced clinician (69%). Specificity of the diagnosis by the experienced dermatologist was higher (99%) than that of the inexperienced clinician (94%) and the computer assessment (74%). Notably, computer analysis gave a higher number of false positives (26%) compared with the experienced dermatologist (0.6%) and the inexperienced clinician (5.5%).

CONCLUSIONS

Our results indicate that analysis either by a trained dermatologist or an artificial neural network-trained computer can improve the diagnostic accuracy of melanoma compared with that of an inexperienced clinician and that the computer diagnosis might represent a useful tool for the screening of melanoma, particularly at centres not experienced in dermoscopy.

Human cholecystokinin-A receptor is not an oncofetal protein

The CCK-A (cholecystokinin-A) receptor is selectively expressed by human pancreatic adenocarcinomas, suggesting a possible role in pancreatic tumorigenesis. In animals, pancreatic CCK receptor expression varies during ontogeny and neoplastic transformation. This study examined the temporal expression of CCK receptors in human fetal, postnatal, and adult pancreas to determine whether the appearance of CCK-A receptors in pancreatic adenocarcinomas reflected oncofetal antigen or pancreatic neoantigen expression. Messenger ribonucleic acid (mRNA) was isolated from six paraffin-embedded normal pancreatic autopsy specimens ranging in age from 17 weeks postfertilization through 26 days following full-term delivery, and samples of adult human tissues, including pancreas and pancreatic adenocarcinoma. Using reverse transcription-polymerase chain reactions, CCK-B receptor mRNA was expressed in all specimens of normal fetal and postnatal human pancreas, adult pancreas, and pancreatic adenocarcinomas. CCK-A receptor mRNA was selectively expressed only in pancreatic adenocarcinomas. These data suggest that selective CCK-A receptor expression in pancreatic adenocarcinomas reflects neoantigen expression in humans.

Macro approach and fuzzy modeling of entrapped biocatalyst

The interactions between a strain of Saccharomyces cerevisiae and an alginate matrix are investigated to ascertain the main factors affecting the bioreaction evolution. During the tests several parameters (glucose, ethanol, calcium ion and biomass concentration, pH, and alginate bed diameter) were evaluated, coupled with microscopic investigation inside the beads to determine the spatial biomass distribution. A detailed analysis of macro parameters and a correlation among them are proposed using a fuzzy algorithm. A global two-step fuzzy model results in which biomass distribution inside the beads is represented as a hidden parameter.

Effect of L-carnitine on human immunodeficiency virus-1 infection-associated apoptosis: a pilot study

The Fas/Fas ligand system is involved in uncontrolled apoptosis, which ultimately leads to the loss of T lymphocytes in human immunodeficiency virus (HIV)-infected individuals. The signal transduced by Fas receptor involves the activation of an acidic sphingomyelinase, sphingomyelin breakdown, and ceramide production. Our recent reports have shown that L-carnitine inhibits Fas-induced apoptosis and ceramide production both in vitro and in vivo. The aim of this study was to study, in a preliminary fashion, the impact of long-term L-carnitine administration on CD4 and CD8 absolute counts, rate, and apoptosis in HIV-1-infected subjects. The generation of cell-associated ceramide and HIV-1 viremia was also investigated. Eleven, asymptomatic, HIV-1-infected subjects, who refused any antiretroviral treatment despite experiencing a progressive decline of CD4 counts, were treated with daily infusions of L-carnitine (6 g) for 4 months. Immunologic and virologic measures and safety were monitored at the start of the treatment and then on days 15, 30, 90, and 150. L-carnitine therapy resulted in an increase of absolute CD4 counts, which was statistically significant on day 90 and 150 (P = . 010 and P = .019, respectively). A positive, not significant trend was also observed even in the change in absolute counts of CD8 lymphocytes. L-carnitine therapy also led to a drop in the frequency of apoptotic CD4 and CD8 lymphocytes. This reduction occurred gradually, but changes in actual values between each time point and baseline were strongly significant (P = .001 at the end of the study compared with the baseline). A strong reduction (P = .001) in cell-associated ceramide levels was found at the end of the study. In general, HIV-1 viremia increased slightly. No toxicity related to L-carnitine therapy was observed and dose reductions were not necessary. In HIV-1-infected subjects, long-term infusions of L-carnitine produced substantial increases in the rate and absolute counts of CD4 and, to a lesser degree, of CD8 lymphocytes. This was paralleled by a reduced frequency of apoptotic cells of both subgroups and a decline in the levels of ceramide. No clinically relevant change of HIV-1 viremia was observed.

[Family history and risk of insulin-dependent diabetes mellitus: a population-based case-control study]

Insulin-dependent diabetes mellitus (IDDM) is a worldwide occurrence disease of childhood with genetic, environmental and familial risk factors. Our study aims to evaluate family history as a determinant of IDDM. In a population-based case-control study informations on all incident IDDM cases, age 0-14, diagnosed between January 1st 1990 and December 31st 1996 were taken from the IDDM population-based register of the Abruzzo Region. The control group was taken from the lists of children attending family paediatricians. The family history data collection for IDDM and non insulin-dependent diabetes (NIDDM) were obtained by a questionnaire, administered to parents. Risk of IDDM associated with familiarity in first and second degree relatives was estimated using conditional regression analysis. Our results show that the risk of developing IDDM is increased by positive family history (OR = 3.99; 95% c.i. 1.56-10.23). The risk of IDDM for children whose fathers or brothers are affected by IDDM is respectively 11 and 20 times higher than for children with no family history. Family history for NIDDM does not influence the risk.

Cholecystokinin A and B receptors are differentially expressed in normal pancreas and pancreatic adenocarcinoma

Cholecystokinin (CCK) plays an important role in pancreatic carcinogenesis. While human CCK-A and -B receptors have been fully characterized, their relative roles in human pancreatic adenocarcinoma remain unclear. Thus, expression of CCK-A and -B receptors in normal human pancreas, pancreatic adenocarcinomas, and other human extrapancreatic tissues and malignancies was examined, using reverse transcription followed by the polymerase chain reaction (RT-PCR). mRNA isolated from 15 normal pancreas specimens, 22 pancreatic adenocarcinomas, and 58 extrapancreatic tissues and tumors was subjected to RT-PCR using primers specific for human CCK-A and -B receptors. Expression of CCK-B receptors was detected in all tissues arising from pancreas and in most extrapancreatic tissues and tumors. In contrast, CCK-A receptors exhibited a more selective pattern of expression in gall bladder, intestine, brain, ovary, spleen, and thymus. Of significance, CCK-A receptors were expressed selectively in all pancreatic adenocarcinomas, but not in any normal pancreas specimens. In situ hybridization, using receptor-specific riboprobes, localized CCK-A receptor expression to ductal cells, the presumed origin of most human pancreatic adenocarcinomas. Southern blot analysis revealed no evidence of CCK-A receptor gene amplification or rearrangement in pancreatic adenocarcinomas. Because of its selective expression, the CCK-A receptor may serve as selective biomarker for pancreatic adenocarcinoma.

K-ras and p53 mutations in aberrant crypt foci and colonic tumors from colon cancer patients

Aberrant crypt foci (ACF) are microscopic lesions which can be detected, after methylene blue staining, in the overtly normal looking colonic mucosa of cancer patients. ACF have been postulated to be precursor lesions which develop into colorectal cancer. Mutations of K-ras and p53 are two important genetic events implicated in colon carcinogenesis. Mutations in K-ras are detectable at earlier stages, while mutations in p53 are detectable at later stages of colon carcinogenesis. Our objective was to compare the nature of genetic alterations in K-ras (codon 12 and 13) and in p53 (exon 4-9) between ACF and corresponding colonic tumors from cancer patients. ACF with > or =20 crypts/focus were harvested from overtly normal looking colonic mucosa of cancer patients at a distance of (approx.) 5 cm from the site of colonic tumors. The colonic tumors and ACF samples were compared for K-ras codon 12 and 13 base pair sequence, using DNA sequencing and for p53 (exon 5-9) allelic types, using PCR-SSCP and DNA sequencing. The results demonstrated a perfect correlation in terms of the type of K-ras allele (wild or mutated) between the ACF (> or =20 crypts/focus) and corresponding colonic tumors in 11/13 cancer patients. Analyses of p53 mutations demonstrated the presence of p53 mutations in colonic carcinomas from 10/13 patients. However, p53 mutations could be detected in an ACF from only 1/13 patient. The results provides further evidence to the role of ACF as precursor to colon cancer. The presence of an identical K-ras as well as p53 mutation in an ACF and the corresponding colonic carcinoma in a patient suggests the possibility of existence of ACF that may be at a more advanced stage in the sequence of colonic tumorigenesis than others. In conclusion, the results suggest that a subset of ACF with higher multiplicity might be considered more likely to progress to more advanced lesions and should be explored as markers of colon cancer risk.

Activation of Raf-1 in human pancreatic adenocarcinoma

Point mutations in the Ras oncogene cause Ras to remain in its active GTP-bound state sending signals downstream continuously. Since 75 to 90% of all human pancreatic ductal adenocarcinomas harbor activating mutations at codon 12 of the K-ras oncogene it was our belief that Raf-1-MEK-MAPK will be activated in the majority of human pancreatic cancers. The aim of this study was to confirm activation of Raf-1 in K-ras mutant human pancreatic cancer. Additionally, we sought to determine if Raf-1 activation differed in K-ras mutant and nonmutant pancreatic cancer. Furthermore, we were interested in determining if Raf-1 activation in pancreatic cancer led to subsequent activation of downstream effectors such as MAP kinase. The presence of mutations in codon 12 of the K-ras oncogene in 14 human pancreatic adenocarcinoma cell lines was determined by use of mutant allele-specific PCR restriction fragment length polymorphism analysis. Raf-1 expression of quiescent cells was determined by immunoblotting using a rabbit anti-human polyclonal antibody and enhanced chemiluminescence. MAP kinase activity was determined by measuring the incorporation of phosphate into Myelin Basic Protein. Seven cell lines were noted to have mutations in codon 12 of K-ras while seven cell lines did not. There was no difference in expression of the 74 kDa-activated form of Raf-1 in K-ras mutant vs K-ras nonmutant cell lines. However, there was a significant increase in MAP kinase activity in the nonmutant cell lines compared to the cell lines with Ras mutations (P = 0.026). We conclude that Raf-1 is expressed in its active form in human pancreatic cancer regardless of K-ras status. However, signalling downstream of Raf-1 differs in cell lines with K-ras mutations compared to those cell lines without K-ras mutations.

Effect of L-carnitine treatment in vivo on apoptosis and ceramide generation in peripheral blood lymphocytes from AIDS patients

Lymphocyte apoptosis in HIV-infected individuals may play a role in T-cell depletion and therefore favor progression to AIDS. In this study, we examined the effects of a short-term (5-day) intravenous treatment with L-carnitine (6 g/day) on apoptosis of CD4 and CD8 cells from 10 AIDS patients. L-carnitine administration has been shown to induce a strong reduction in the percentage of both CD4 and CD8 cells undergoing apoptosis. Interestingly, the L-carnitine treatment, which did not show relevant side effects in four patients, led to a strong and significant reduction of peripheral blood mononuclear cell-associated ceramide, an intracellular messenger of apoptosis, that positively correlated with the decrease of apoptotic CD4- and CD8-positive cells. These results suggest that L-carnitine could be an effective antiapoptotic drug in the treatment of AIDS patients.

Amplification of AKT2 in human pancreatic cells and inhibition of AKT2 expression and tumorigenicity by antisense RNA

We previously demonstrated that the putative oncogene AKT2 is amplified and overexpressed in some human ovarian carcinomas. We have now identified amplification of AKT2 in approximately 10% of pancreatic carcinomas (2 of 18 cell lines and 1 of 10 primary tumor specimens). The two cell lines with altered AKT2 (PANC1 and ASPC1) exhibited 30-fold and 50-fold amplification of AKT2, respectively, and highly elevated levels of AKT2 RNA and protein. PANC1 cells were transfected with antisense AKT2, and several clones were established after G418 selection. The expression of AKT2 protein in these clones was greatly decreased by the antisense RNA. Furthermore, tumorigenicity in nude mice was markedly reduced in PANC1 cells expressing antisense AKT2 RNA. To examine further whether overexpression of AKT2 plays a significant role in pancreatic tumorigenesis, PANC1 cells and ASPC1 cells, as well as pancreatic carcinoma cells that do not overexpress AKT2 (COLO 357), were transfected with antisense AKT2, and their growth and invasiveness were characterized by a rat tracheal xenotransplant assay. ASPC1 and PANC1 cells expressing antisense AKT2 RNA remained confined to the tracheal lumen, whereas the respective parental cells invaded the tracheal wall. In contrast, no difference was seen in the growth pattern between parental and antisense-treated COLO 357 cells. These data suggest that overexpression of AKT2 contributes to the malignant phenotype of a subset of human ductal pancreatic cancers.

Secretion of gelatinases by human pancreatic cancer cell lines: lack of correlation with invasive ability

Twelve immortalized human cell lines derived from primary or metastatic lesions from pancreatic carcinomas were studied with respect to their in vitro invasiveness and motility. Various levels of invasive capacity and chemotactic responses were found. Zymograms of cells conditioned media were carried out to determine the role of metalloproteinases in pancreatic cancer invasion. No correlations were found, however, between invasive capacity of pancreatic carcinoma cell lines and gelatinase secretion. Putative reasons for these findings are discussed.

[The X-ray fluorescence (XRF) spectrometry of biomaterials used in dentistry. 2]

In this work we analyze the following biomaterial: biomaterials used in this study are: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non reabsorbable thin Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2, Osprogel, Bio-Oss, Biostite, Osprovit, Merck Hydroxiapatite. The quantitative XRF analysis was performed by a Philips PW 1480 with Rh tube. This research, besides underlining the possibility of applying the XRF method to the analysis of biomaterials. This study, shows the facility and the rapidity in the preparation of samples and standards in the form of tablets to undergo the analysis: furthermore the study shows the possibility of verify the analysis on the same sample in the future, because the tablet if well conserved, does not deteriorate. We can also verify a good analytic accuracy both for the principal elements (Ca, P) and for trace elements. The analyses show a moderate variability in the Ca/P ratio in the hydroxylapatites, and a greater variability in the secondary and trace elements.

[A critical note on bioceramics]

In this note I, the authors point out the uncertainty and confusion which exists in the bioceramics field. They then list the calcium phosphate biomaterials today in use.

Immunohistochemical analysis of p53 expression in human pancreatic carcinomas

Alterations in the p53 tumor suppressor gene are involved in the pathogenesis of diverse human cancers. Immunohistochemical detection of the p53 protein has been strongly correlated with mutations in the p53 gene. Fifty-four human exocrine pancreatic tumors of American, Japanese, and Senegalese origin and six xenotransplanted human pancreatic carcinoma cell lines were investigated immunohistochemically with monoclonal anti-p53 antibodies pAb 1801 and BP53-12. Positive nuclear p53 immunoreactivity was detected in 37% of paraffin-embedded primary tumors (21.8% in the Japanese group, 52.6% in the American group) and in 50% of xenotransplanted carcinoma cell lines. Since several intraductal papillary adenocarcinomas exhibited positive p53 immunostain, it seems probable that alterations in this tumor suppressor gene occur relatively early in the process of pancreatic carcinogenesis. No clear correlation was established between p53-positive immunohistochemical staining and tumor stage and histologic appearance, nor with patient age, sex, or survival time. In contrast to ductal carcinomas and intraductal papillary adenocarcinomas, none of the mucinous or adenosquamous pancreatic carcinomas exhibited positive nuclear staining for p53. The fact that more than half of the ethanol-fixed fine-needle aspirates were positive for p53 suggests that this type of immunostain may be of potential diagnostic significance. An investigation of a large series of pancreatic tumors is needed to further evaluate the relationship between p53 alterations and clinicopathologic features in human pancreatic cancer.

Benzo[a]pyrene-induced murine skin tumors exhibit frequent and characteristic G to T mutations in the p53 gene

Human tobacco-related cancers exhibit a high frequency of G to T transversions in the mutation hot spot region of the p53 tumor suppressor gene, possibly the result of specific mutagens in tobacco smoke, most notably benzo[a]pyrene (B[a]P). No in vivo animal model of B[a]P-induced tumorigenesis has been used, however, to substantiate these molecular epidemiological data experimentally. Direct DNA sequence analysis of the hot spot region (exons 5-8 inclusive) of murine p53 was performed in 20 skin tumors induced by a complete carcinogenesis protocol with B[a]P. Sequence analyses revealed numerous heterozygous missense mutations in carcinomas, specifically in exons 7 and 8 of the p53 gene, and targeting exclusively guanine residues. Moreover, 70% (5/7) of the mutations characterized were G to T transversions. In contrast, direct DNA sequence analysis of 36 skin tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) in either a complete carcinogenesis protocol or in a two-stage carcinogenesis protocol revealed a 30% frequency of heterozygous p53 mutations, with the majority of mutations found in carcinomas, but only a single G to T transversion (1/8). Thus, while mutation frequencies are similar, the pattern and type of p53 mutations in B[a]P-induced skin tumors differs significantly from the mutation spectra in DMBA-induced squamous neoplasias. These in vivo findings in B[a]P-induced tumors lend support to in vitro and molecular epidemiological evidence, suggesting that the p53 tumor suppressor gene may be a selective target of metabolically activated B[a]P species etiologically associated with human tobacco-related cancers.

Human pancreatic carcinomas and cell lines reveal frequent and multiple alterations in the p53 and Rb-1 tumor-suppressor genes

The molecular pathology of human pancreatic cancer is poorly understood, particularly with regard to the role of known tumor-suppressor genes. We have examined the expression of the p53 and Rb-1 tumor-suppressor genes in seven human pancreatic carcinoma cell lines and 10 primary pancreatic carcinomas. Examination of the Rb-1 gene by Northern hybridization and immunoprecipitation analyses revealed the absence of Rb-1 protein expression in two cell lines. Moreover, regions of absent nuclear staining in two primary pancreatic carcinomas were detected by immunohistochemical analysis. Investigation of p53 by Southern, Northern, immunohistochemical and immunoprecipitation analyses revealed multiple abnormalities, including gross rearrangements in two cell lines, the absence of detectable p53 transcript in two cell lines and a truncated transcript in one line. Six cell lines overexpressed p53 protein, while one line revealed the absence of p53 product by immunohistochemical and immunoprecipitation analyses. Sequence analysis of exons 5-8 of the p53 gene confirmed these analyses, revealing missense mutations in all seven cell lines in codons 181, 220, 248, 249, 265, 272 and 273. Of 10 mutations identified, nine were transitions and 50% were in codon 273. Immunohistochemical analyses of frozen primary pancreatic carcinomas revealed positive nuclear staining for p53 in 40% of cases. Mutations were identified in codons 238 and 286 and in intron 9 in several representative specimens. Alterations in the p53 and Rb-1 genes may be important features in the development of human pancreatic cancer.

Alterations in the expression of uvomorulin and Na+,K(+)-adenosine triphosphatase during mouse skin tumor progression

Uvomorulin (E-cadherin), a cell adhesion molecule, and Na+,K(+)-adenosine triphosphatase (ATPase), a marker protein of the basal-lateral cell membrane domains of polarized epithelial cells, were investigated in a group of mouse skin tumors induced by a two-stage chemical carcinogenesis protocol and in cell lines derived from mouse skin papillomas and squamous cell carcinomas (SCC). Although these two markers were present in benign tumors and in nontumorigenic cell lines, the Na+,K(+)-ATPase showed an altered pattern of distribution that included the presence of enzyme not only in the basolateral domain but also on the apical domain of the cell membrane of basal and spinous cells in well-differentiated squamous cell carcinomas (SCC). In higher grade SCC, a loss of Na+,K(+)-ATPase immunoreactivity was simultaneously detected with a marginal or absent expression of uvomorulin. The more differentiated SCC and papillomas expressed less uvomorulin immunoreactivity than normal epidermal cells. Both markers were seen in tumor cell lines that produced well-differentiated SCC after subcutaneous inoculation into nude mice. Neither Na+,K(+)-ATPase nor uvomorulin could be detected in cell lines that produced high grade, poorly differentiated SCC. Northern blots confirmed the absence of uvomorulin mRNA in these highly malignant cell lines. These data indicate that progression from premalignant papilloma to low-grade SCC and subsequently to high-grade SCC is accompanied by loss of epithelial cell polarity as detected by changes in Na+,K(+)-ATPase and by decreased or absent expression of uvomorulin in tumors and cell lines characterized by an advanced malignant phenotype.

Alterations of the p53 tumor suppressor gene during mouse skin tumor progression

The two-stage murine skin tumorigenesis model is widely used to study the development of squamous cell neoplasias. We have investigated expression of the p53 and retinoblastoma tumor suppressor genes in eight murine skin tumor cell lines of varied histopathology and malignant potential, in seven in vivo-derived clones from these cell lines, and in 39 primary short-term cultures of similarly induced skin tumors at various stages of tumor progression. One squamous cell carcinoma cell line and three more malignant clones derived from it revealed mutations of the p53 protein by immunoprecipitation analyses despite normal-sized p53 transcripts. Sequence analysis identified the nature of the point mutations in these lines, a G----C transversion in codon 132. Mouse retinoblastoma transcripts and protein were unaltered in all the cell lines examined. Among short-term cultures of skin tumors, the p53 gene appeared normal in all papillomas and early well-differentiated carcinomas by Southern and immunoprecipitation analyses. In contrast, four of eight tumors from later stages of promotion (50-60 weeks) possessed alterations in p53, including loss of the p53 product, and loss of immunoreactivity with a murine-specific antibody recognizing only wild-type p53 protein. Loss of heterozygosity at the p53 locus was similarly observed in several more malignant tumors from later stages of promotion. In contrast retinoblastoma expression was normal regardless of the stage of promotion or histological grade of the tumor. Direct sequence analyses of exons 5 through 8 of the p53 gene in eight advanced murine skin tumors revealed a 25% incidence of p53 mutations. These point mutations were located in codons 245 and 263. Collectively, these data indicate that alterations in the p53 gene occur in 25 to 50% of murine skin tumors induced by the two-stage tumorigenesis protocol and are later events in murine skin tumor progression. Moreover, these alterations are associated with tumors possessing a more malignant and/or poorly differentiated phenotype.

Detection of p53 in primary lung tumors and nonsmall cell lung carcinoma cell lines

Immunohistochemical analysis of p53, a nuclear protein involved in the development of numerous human tumors, was performed in a series of 50 primary nonsmall cell lung carcinomas and in a group of eight lung carcinoma cell lines. Using two mouse monoclonal antibodies, PAb1801 and PAb421, sixteen of thirty-five (45.7%) lung adenocarcinomas and seven of fifteen (46.6%) squamous cell carcinomas showed marked-to-moderate immunoreactivity. In fifty-six percent of the positive tumors more than 40% of all cells were p53 positive, and in only 17% of positive tumors the percentage of immunostained cells was less than ten. Although the number of p53 negative adenocarcinomas without metastasis was larger than the number of p53 positive tumors without metastasis, there were not clear differences between p53 positive and negative tumors with metastasis. Furthermore, six adenocarcinomas that infiltrated the pleura and/or the thoracic wall were p53 positive, whereas only two of these invasive tumors were p53 negative. From eight cell lines studied, six were positive for p53. A good correlation between immunocytochemistry and immunoprecipitation was observed. Two tumorigenic and metastatic cell lines, Calu 1 and Calu 6, that were not immunoreactive also showed lack of protein by immunoprecipitation, as well as absence of mRNA in Northern analysis. In addition, Calu 1 showed an important gene deletion. These observations point to the fact that deletions and alterations in transcription of the p53 gene could coincide with or eventuate in an advanced malignant phenotype that nevertheless results in a p53 negative immunostain. Although this type of change cannot be detected immunohistochemically in primary tumors without further molecular analysis, the results presented herein indicate that p53 can be detected immunohistochemically in a majority of lung tumors and that there is a tendency for more advanced adenocarcinoma stages to exhibit positive p53 immunostain.

Progression of squamous carcinoma cells to spindle carcinomas of mouse skin is associated with an imbalance of H-ras alleles on chromosome 7

Analysis of benign and malignant mouse skin tumors had previously shown that amplification of a mutant H-ras allele or loss of the normal allele was generally seen only in high grade or spindle cell tumors. The normal:mutant ras gene dosage has been studied directly by polymerase chain reaction amplification of DNA derived from paraffin sections of carcinomas of defined histological types. Some tumors had virtually no signal corresponding to the normal allele and these were invariably spindle cell carcinomas. In four cases where both squamous and spindle cell components could be identified within the same tumor the spindle cell component had a higher mutant:normal gene ratio. Additional experiments on cell lines derived from squamous or spindle cell tumors have demonstrated a good correlation between the ratio of normal:mutant ras and the degree of invasiveness of the cells in in vitro assays.

[Hyalin substance in odontogenic cysts. Histological observations]

The odontogenic cysts contain the hyaline deposits in 69.2%. The hyaline deposits appear as a zone that was continuous with basament membrane or as an irregular deposit within the connective tissue.