Nonrandom karyotypic features in basal cell carcinomas of the skin.

Cytogenetic analysis of short-term cultured 44 basal cell carcinomas (BCC) revealed clonal karyotypic abnormalities in 38 tumors. Relatively complex karyotypes (at least four structural and/or numerical changes per clone) with unbalanced structural as well as numerical aberrations were found in eight (approximately 21%) of the BCC, while the remaining BCC (79%) had simple karyotypes (1 to 3 aberrations per clone). Numerical changes only were found in 16 tumors, 15 BCC displayed both numerical and structural aberrations, and the remaining 7 BCC showed only structural aberrations. Extensive intratumoral heterogeneity, in the form of cytogenetically unrelated clones, was found in 21 tumors, whereas related subclones were present in 10 tumors. In order to obtain an overall karyotypic picture in BCC, the findings of our previously published 25 BCC have been reviewed. Our combined data indicate that BCC are characterized by nonrandom karyotypic patterns. A large subset of BCC is characterized by nonrandom numerical changes, notably, +18, +X, +7, and +9. Structural rearrangements often affect chromosomes 1, 4, 2, 3, 9, 7, 16, and 17. A number of chromosomal bands are frequently involved, including 9q22, 1p32, 1p22, 1q11, 1q21, 2q11, 4q21, 4q31, 1p36, 2q37, 3q13, 7q11, 11p15, 16p13, 16q24, 17q21, and 20q13. When the genomic imbalance is assessed, it has been shown that several chromosome segments are repeatedly involved in losses, namely loss of the distal part of 6q, 13q, 4q, 1q, 8q, and 9p. A correlation analysis between the karyotypic patterns and the clinico-histopathologic parameters has been undertaken in the 44 BCC of the present series. The cytogenetic patterns show a significant correlation with tumor status (P=.025), that is, that cytogenetically more complex tumors are also those clinically the most aggressive. Also, the frequency of cytogenetically unrelated clones is significantly higher in recurrent BCC than that in primary lesions (P=.05). No clear-cut association has been found between the karyotypic patterns and histologic subtypes or tumor sites.     

Diverse chromosome abnormalities in squamous cell carcinomas of the skin

Short-term cultures from three invasive squamous cell carcinomas of the skin were cytogenetically analyzed. Clonal chromosome aberrations were found in all tumors. In the first case, two of three abnormal clones were related, and in the second case, two of five clones demonstrated cytogenetic similarities. Both clones detected in case 3 had a structural rearrangement in common. Several nonclonal changes were seen in all three cases in addition to the clonal aberrations. None of the rearrangements detected, clonal or nonclonal, corresponds to any of the consistently cancer-associated aberrations known from other neoplasms. The remarkably diverse karyotypic picture of the three squamous cell carcinomas, in particular the finding of unrelated clones in two of them, hints that these neoplasms may be poly-rather than monoclonal. The lack of a common cytogenetic denominator argues that if chromosomal changes are of pathogenetic importance in this tumor type, a wide variety of apparently dissimilar changes exist that are roughly equal in their capacity to malignantly transform skin epithelium.     

Nuclear morphometry in squamous cell carcinomas of canine skin

To investigate the diagnostic and prognostic value of nuclear morphometry in squamous cell carcinomas (SCCs) of canine skin, histological samples from 15 dogs were retrospectively analysed by computerized nuclear morphometry. In each case, the nuclei of at least 100 neoplastic cells were measured, and the mean nuclear area (MNA), standard deviation of MNA (SDa), mean nuclear perimeter (MNP), standard deviation of MNP (SDp), nuclear form factor (FF), and standard deviation of FF (SDf) were calculated. The morphometric data were examined in relation to tumour histological grade. No statistical differences were found between the different grades of SCC in terms of the mean values of SDa, SDp, FF or SDf. The MNA values, however, differed significantly between grades: I and III; I and IV; II and III; II and IV. The MNP values differed significantly between grades: I and III; I and IV; II and IV. The results indicate that nuclear morphometry analysis is a simple and reproducible method that could be used to provide objective diagnostic criteria for cutaneous SCCs in the dog.     

Unique karyotypic abnormalities in a squamous cell carcinoma of the larynx

We have cytogenetically examined short-term cultures from a squamous cell carcinoma of the larynx, a type of carcinoma in which chromosome aberrations have hitherto not been reported. The tumor karyotype was 46,XY,inv(2)(p22q24),t(9;13)(q34;q12),t(11;18)(q23;q21). None of these abnormalities have been described in carcinomas before.     

Immunohistochemical comparison of p16 expression in actinic keratoses and squamous cell carcinomas of the skin.

There are approximately 200,000 new cases of cutaneous squamous cell carcinoma diagnosed each year in the United States, with between 1300 and 2300 deaths per year from metastatic disease. The tumor suppressor p16, encoded by the CDKN2/INK4a locus, has been reported mutated in >or=24% of squamous cell carcinomas. Mutations of the p16 gene have also been found in actinic keratoses, the first identifiable lesion in the continuum from normal skin to squamous cell carcinoma. We hypothesized that there may be an appreciable difference in expression of p16 between normal skin, actinic keratoses, squamous cell carcinoma in situ, and invasive squamous cell carcinoma. Ten actinic keratoses, 10 in situ squamous cell carcinomas, and 10 invasive squamous cell carcinomas were examined using the immunoperoxidase method with antigen retrieval for anti-p16(INK4a) antibody. All 10 actinic keratoses were positive for weak to moderate p16 staining in the lower third to lower half of the epidermis (especially the basal keratinocytes). This staining was significant when compared with the lack of staining seen in normal skin controls. Twenty percent of in situ squamous cell carcinomas had moderate to strong staining in only the lower half to lower two thirds of the epidermis, whereas 70% of the in situ squamous cell carcinomas exhibited full-thickness p16 staining, with no staining in the dermis. Thirty percent of invasive squamous cell carcinomas had full-thickness staining of the in situ component of the lesion, and 100% of invasive squamous cell carcinomas exhibited moderate to strong staining of the invasive component of the lesion. These findings indicate correlation between the increased expression of p16 during the progression of skin from actinic keratosis to in situ squamous cell carcinoma to invasive squamous cell carcinoma. These data may lend further support to the view of the actinic keratosis as a precursor lesion to squamous cell carcinoma.     

Expression of two keratins in basal cell,metatypical, and squamous cell carcinomas of the skin

Using an indirect immunoperoxidase method and monoclonal antibodies, the expression of keratins 8 and 17 is investigated in 53 cases of basal cell carcinoma, 10 cases of metatypical carcinoma, and 3 cases of squamous cell carcinoma. Basal cell carcinoma cells are found to express keratin 17 in all cases and keratin 8 in the majority of them. The levels of these keratins in metatypical carcinoma cells are much lower. In squamous cell carcinoma, the keratins are only expressed in a few fields of vision around areas of keratinization. Comparative microspectrophotometric measurements of the intensities of specific staining show that the histological preparations of basal cell carcinoma have optical densities 6–7 times higher than those of metatypical carcinoma and 10–14 times higher than those of squamous cell carcinoma. It is concluded that the features of keratin expression observed in this study may be of use in the differential diagnosis of skin cancers. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 300–303, September, 1994 Presented by N. K. Permyakov, Member of the Russian Academy of Medical Sciences     

Nonrandom pattern of cytogenetic abnormalities in squamous cell carcinoma of the larynx

Cytogenetic analysis of short-term cultures from 105 squamous cell carcinomas of the larynx (LSCC) revealed clonal chromosome aberrations in 56 tumors. Simple karyotypic changes (less than four aberrations per clone) were found in 24 cases, and the remaining 32 tumors had complex karyotypes with multiple numerical as well as unbalanced structural rearrangements. Extensive intratumor heterogeneity, in the form of multiple related subclones or unrelated clones, was observed in a large fraction of the tumors. The structural changes most often affected chromosomes 3, 1, 11, 7, 2, 15, 5, 4, 8, and 12, with rearrangements in the centromeric regions, i.e., the centromeric bands p10 and q10 and the juxtacentromeric bands p11 and q11, accounting for 43% of the total breakpoints. The most common imbalances brought about by numerical and unbalanced structural rearrangements were loss of chromosomal region 3p21-pter, chromosome arms 4p, 6q, 8p, 10p, 13p, 14p, 15p, and 17p, and gain of chromosomal regions 3q21-qter, 7q31-pter, and 8q. Among 17 recurrent aberrations identified, the most common were i(8q), hsr(11)(q13), i(3q), i(5p), and del(3)(p11). No statistically significant association was found between major karyotypic features and histological differentiation or TNM stage. The karyotypic features of the LSCC were also compared with previously published oral SCC, a subgroup of SCC that has been more extensively characterized cytogenetically. No clear-cut karyotypic differences were found between LSCC and oral SCC, with the exception that i(8q) was significantly more frequent among the latter.     

Expression of apoptotic and cell proliferation regulatory proteins in keratoacanthomas and squamous cell carcinomas of the skin

The aim of this study was to investigate the expression of p53, caspase-3, bcl-2, MIB-1, and PCNA to validate more objective methods to differentiate squamous cell carcinoma and keratoacanthoma, as well as to understand their pathogenesis with accuracy. A total of 52 cases of histopathologically diagnosed keratoacanthoma in the proliferative stage and 56 cases of well-differentiated squamous cell carcinoma were selected in this study. The expression was evaluated by means of immunohistochemistry. Bcl-2 immunoreactivity was weak or absent in the majority of cases, either in squamous cell carcinoma or in keratoacanthoma. PCNA-positive cells did not show differences between two lesions evaluated. On the other hand, MIB-1 was statistically significant (p<0.05) between squamous cell carcinomas and keratoacanthomas. Moreover, p53 and caspase-3 were overexpressed in squamous cell carcinomas. Together, these results suggest that the biological behavior of the well-differentiated squamous cell carcinomas of the skin may be associated with cellular proliferation and/or deregulation of cell death, indicated by increased expression of the MIB-1 and apoptotic proteins p53 and caspase-3, respectively.     

Microstaging of squamous cell carcinomas

The clinical classification of squamous cell carcinoma, which was established primarily by the International Union Against Cancer (UICC), does not permit optimal estimation of expected metastasis. The authors' results indicate that metastasis can be more accurately estimated on the basis of invasion depth, histopathologic grading, and especially tumor thickness. One essential advantage of these criteria is that they can be established by a histopathologist. It is interesting to note that in the authors' collective no carcinoma less than 2 mm thick metastasized, that is, a relatively high percentage of carcinomas (48%) can be graded as no-risk carcinomas. The risk of metastasis for undifferentiated carcinomas greater than 6 mm thick that have infiltrated the musculature, the perichondrium, or the periosteum, however, is quite high. Tumors between 2 and 6 mm thick with moderate differentiation and a depth of invasion that does not extend beyond the subcutis can be classified as low-risk carcinomas.     

Angiogenesis in squamous cell carcinomas of canine skin: an immunohistochemical and quantitative analysis

In a number of recent papers, the intratumoral microvessel density (iMVD) has been described as a promising new prognostic factor. In this study, the angiogenic rate was evaluated immunohistochemically for platelet endothelial cell adhesion molecule (CD31) in 15 squamous cell carcinomas (SCCs) of canine skin. Computer image analysis was used to measure the iMVD, which increased progressively from differentiation grade I to IV. The iMVD was consistently and significantly greater in the poorly differentiated SCC cases. The correlation of angiogenesis data with differentiation grade of canine SCCs suggests that the iMVD value may provide an additional criterion for evaluating the intrinsic malignancy and growth potential of such tumours.     

Nonrandom chromosomal aberrations and cytogenetic heterogeneity in gallbladder carcinomas.

Chromosome banding analysis of 11 short-term cultured gallbladder carcinomas revealed acquired clonal aberrations in seven tumors (five primary and two metastases). Three of these had one clone, whereas the remaining four were cytogenetically heterogeneous, displaying two to seven aberrant clones. Of a total of 21 abnormal clones, 18 had highly complex karyotypes and three exhibited simple numerical deviations. Double minutes and homogeneously staining regions were observed in one and two carcinomas, respectively. To characterize the karyotypic profile of gallbladder cancer more precisely, we have combined the present findings with our three previously reported cases, thereby providing the largest cytogenetic database on this tumor type to date. A total of 287 chromosomal breakpoints were identified, 251 of which were found in the present study. Chromosome 7 was rearranged most frequently, followed by chromosomes 1, 3, 11, 6, 5, and 8. The bands preferentially involved were 1p32, 1p36, 1q32, 3p21, 6p21, 7p13, 7q11, 7q32, 19p13, 19q13, and 22q13. Nine recurrent abnormalities could, for the first time, be identified in gallbladder carcinoma: del(3)(p13), i(5)(p10), del(6)(q13), del(9)(p13), del(16)(q22), del(17)(p11), i(17)(q10), del(19)(p13), and i(21)(q10). The most common partial or whole-arm gains involved 3q, 5p, 7p, 7q, 8q, 11q, 13q, and 17q, and the most frequent partial or whole-arm losses affected 3p, 4q, 5q, 9p, 10p, 10q, 11p, 14p, 14q, 15p, 17p, 19p, 21p, 21q, and Xp. These chromosomal aberrations and imbalances provide some starting points for molecular analyses of genomic regions that may harbor genes of pathogenetic importance in gallbladder carcinogenesis. Genes Chromosomes Cancer 26:312-321, 1999.     

Expression of vascular endothelial growth factor in basal cell tumours and in squamous cell carcinomas of canine skin

The expression of vascular endothelial growth factor (VEGF) was evaluated immunohistochemically in 20 basal cell tumours (BCTs) and 15 squamous cell carcinomas (SCCs) of canine skin. VEGF was identified in all the SCCs and was particularly striking in those occurring on the toe. On the other hand, VEGF was absent in the great majority of BCTs, occurring only in those of the solid type. The results suggest that presence of VEGF is a useful additional criterion for evaluating malignancy and growth potential in tumours of these types.     

Cysteine protease and its inhibitor in experimentally produced squamous cell carcinomas in hairless mouse skin

Squamous cell carcinomas (SCC) were experimentally produced in hairless mouse skin, and cysteine protease and its inhibitor were simultaneously purified from extracts of 1 g of tissue of SCC and normal skin. Activity of cysteine proteinases, Mr greater than 50,000 and Mr 28,000, increased in SCC compared to those in normal skin. SCC also showed elevation of cysteine proteinase inhibitor activity and Mr 13,000 and Mr 82,000 inhibitors were purified. Mr 13,000 inhibitor was found to have biochemical properties which were the same as those of the inhibitor present in normal skin. Mr 82,000 inhibitor was not detectable in normal skin and it differed from a serum inhibitor with a similar Mr in terms of activity and stability at acidic pH. The findings suggest that the increased activity of both cysteine proteases and endogenous inhibitors may be involved in the regulatory mechanisms of malignant cell metabolism and tissue remodeling associated with SCC development.     

Statistical analyses of karyotypic complexity in head and neck squamous cell carcinoma

More than 250 head and neck squamous cell carcinomas (HNSCCs) with clonal chromosomal abnormalities have been reported. Even though the pattern of aberrations is nonrandom, no specific primary or secondary karyotypic abnormalities have been identified. One explanation for the still-rudimentary understanding of the cytogenetic evolution in HNSCC could be the pronounced karyotypic complexity seen in these tumors. In an attempt to overcome this difficulty, we have applied several statistical methods such as hierarchical cluster analysis, multidimensional scaling, and k-means clustering, which allow the identification and interpretation of karyotypic pathways, as well as establishing a temporal order of chromosomal imbalances on 241 published and 70 previously unpublished HNSCC karyotypes. From the analysis of the distribution of the number of imbalances per tumor we suggest that the carcinomas evolve through three phases representing different stages of chromosomal instability. Two major cytogenetic pathways, one dominated by gains and another by losses, were identified by means of principal component analysis. These were initiated by +7 and by any of the aberrations 1p-, 3p-, or 7q-, respectively.     

Oncogene interaction in basal cell carcinomas of human skin.

The expression of the p53 protein (p53) was compared with those of several oncogenes including c-fos (Fos), c-jun (Jun), and epidermal growth factor receptor (EGFR1) using immunohistochemistry in frozen and paraffin-embedded sections of 25 basal cell carcinomas (BCCs) to find out any correlation between p53 and oncogenes in the pathogenesis of human BCC. In normal skin, positive reactions were obtained for EGFR1 and Fos, while p53 and Jun were negative in all cases. In the lesions, EGFR1 was observed in all cases and p53 was positive in 9 of 25 (36%). Fos was expressed in 21 of 25 (84%) and four negative cases were all p53-positive; this negative correlation between p53 and Fos staining was statistically significant (P < 0.01). Jun was detected in 14 of 20 (70%) and no significant relationship was observed between the expression of Jun and Fos or p53. These data suggest the possibility of down regulation of Fos expression by high levels of p53 protein. Further work is necessary to determine the mechanism of this interaction.     

Differences in the vascular patterns of basal and squamous cell skin carcinomas explain their differences in clinical behaviour

Tumour angiogenesis is essential for tumour growth and appears to play an important role both at the transition from hyperplasia to invasive growth and at a late stage in the dissemination process. Basal cell carcinomas (BCCs) and trichoepitheliomas (TEs) are related tumours that share the properties of invasive growth but without the capacity to metastasize. Squamous cell carcinomas (SCCs) of the skin are derived from a similar cell type and they have both invasive and metastatic potential. The aim of this study was to investigate whether the behaviour of these tumours could be explained by differences in their microvasculature. The study looked both qualitatively and quantitatively at the microvasculature of BCCs (n=50) and TEs (n=33) and compared them with normal skin (n=6) and with SCCs of the skin (n=22). Vessel counts were performed using a standard graticule count method after immunohistochemical staining for CD31. Counts were made of blood vessels in the stroma surrounding the tumour and also for vessels in the body of the tumour. The stromal counts for all the tumour groups differed significantly from normal skin. The SCC counts differed significantly from the counts for the BCCs and TEs. There was no significant difference between the counts for different subtypes of BCC or TE groups. While vessels could be found in the body of the SCCs, none was seen in the nodular BCC or the TE groups. There was no correlation between the vascular density and the depth of invasion. Overall, invasive growth correlated with an angiogenic response in the stroma, while metastatic potential correlated with microvessels being present in the body of the tumour.