Distribution of basement membrane in squamous cell carcinoma of the head and neck

Precancerous Lesions of the Head and Neck Region and Their Stromal Aberrations: Piecemeal Data

Head and neck squamous cell carcinomas (HNSCCs) develop through a series of precancerous stages from a pool of potentially malignant disorders (PMDs). Although we understand the genetic changes that lead to HNSCC, our understanding of the role of the stroma in the progression from precancer to cancer is limited. The stroma is the primary battleground between the forces that prevent and promote cancer growth. Targeting the stroma has yielded promising cancer therapies. However, the stroma at the precancerous stage of HNSCCs is poorly defined, and we may miss opportunities for chemopreventive interventions. PMDs already exhibit many features of the HNSCC stroma, such as inflammation, neovascularization, and immune suppression. Still, they do not induce cancer-associated fibroblasts or destroy the basal lamina, the stroma's initial structure. Our review aims to summarize the current understanding of the transition from precancer to cancer stroma and how this knowledge can reveal opportunities and limitations for diagnostic, prognostic, and therapeutic decisions to benefit patients. We will discuss what may be needed to fulfill the promise of the precancerous stroma as a target to prevent progression to cancer.

Unraveling the ECM-Immune Cell Crosstalk in Skin Diseases

The extracellular matrix (ECM) is a complex network of proteins and proteoglycans secreted by keratinocytes, fibroblasts and immune cells. The function of the skin ECM has expanded from being a scaffold that provides structural integrity, to a more dynamic entity that is constantly remodeled to maintain tissue homeostasis. The ECM functions as ligands for cell surface receptors such as integrins, dystroglycans, and toll-like receptors (TLRs) and regulate cellular signaling and immune cell dynamics. The ECM also acts as a sink for growth factors and cytokines, providing critical cues during epithelial morphogenesis. Dysregulation in the organization and deposition of ECMs lead to a plethora of pathophysiological conditions that are exacerbated by aberrant ECM-immune cell interactions. In this review, we focus on the interplay between ECM and immune cells in the context of skin diseases and also discuss state of the art therapies that target the key molecular players involved.

Does pTis exist in HPV-driven tonsillar carcinomas? An ultrastructural review and examination of two cases

Many tonsillar tumors present clinically as cervical nodal metastases and the primary tumor is often difficult to find. HPV-driven tonsillar carcinoma begins in the reticulated crypt epithelium, possibly through viral integration. The basement membrane is not complete in the reticulated crypt epithelium, which may enhance the immune function. We examined the reticulated crypt epithelium in a normal case and five neoplastic tonsils with cervical metastasis as the presenting symptom to further investigate whether tonsil carcinoma in-situ exists. Our results suggest that in-situ carcinoma may need to be excluded from the future staging for human papilloma virus associated tonsillar tumors.

Leukemoid reaction as a paraneoplastic syndrome in hypopharyngeal squamous cell carcinoma with cutaneous metastasis: an exceedingly rare occurrence

Head and neck squamous cell carcinoma is considered a locoregional disease, with a distinct chance of metastasis, however, skin is an unusual site. Haematological paraneoplastic syndromes are even rarer, and may be the only presenting feature in these malignancies, producing diagnostic confusion. Cutaneous metastasis, in addition to signifying poor response to treatment and prognosis, can cause diagnostic difficulty if the metastasis is located with an occult primary, and is associated with a higher incidence of multiple synchronous primaries. This article describes a 52-year-old patient with multiple swellings on the left side of the neck and hoarseness of voice. On evaluation, the multiple swellings were found to be cutaneous metastasis from a hypopharyngeal squamous cell carcinoma, with a leukemoid reaction. He opted for palliative radiotherapy and succumbed to his illness within 3 months of presentation. This article discusses the importance of this unusual presentation and diagnostic difficulties associated with it.

The Effects of Fixation and Dehydration on the Histological Quality of Undecalcified Murine Bone Specimens Embedded in Methylmethacrylate

Histological evaluation is a complex, multistep process culminating in tissue staining. All of the steps leading up to the staining affect the final quality, but too often the effects of these preparations are not given enough consideration. Fixatives in particular usually are chosen not for efficacy but for convenience and availability. This study attempts to create guidelines for selecting fixatives for bone tissue histological evaluation. We compared two of the most widely used fixatives, ethanol and formalin, in their use on mouse tibias embedded in methylmethacrylate and subsequently stained with toluidine blue, safranin O, or Von Kossa. Our results show that ethanol fixation (70%) and subsequent processing in methylmethacrylate gives better staining results for bone cell related elements than fixing in 10% neutral buffered formalin with the same processing and embedding techniques. Further we demonstrated than an additional acetone dehydration and clearing step allowed for even better visualization in bone specimens fixed with 70% ethanol. However, the additional acetone step did not enhance visualization in bone specimens fixed with 10% neutral buffered formalin. Finally, marrow elements were more easily visualized when fixed with formalin as opposed to ethanol.

Expression of extracellular matrix-laminin in oral squamous cell carcinoma: an immunohistochemical study

AIM

To evaluate the expression of laminin in various grades of oral squamous cell carcinoma (OSCC) in order to determine whether this protein can be used as a marker for early detection and elucidation of oral cancer.

MATERIALS AND METHODS

Immunohistochemical staining for laminin was done on 60 selected archival blocks of histopathologically diagnosed cases of primary OSCC and the laminin expression was compared between the different histopathological grades of primary OSCC. The statistical analysis was performed by using Chi-square (X square) test and Gaussiantest with a probability of p > 0.05 was considered as significant.

RESULTS

It was observed that laminin expression decreased with tumor progression which may be correlated to the tumor aggressiveness.

CONCLUSION

There was a gradual decrease of laminin staining with decreasing cellular differentiation, with differentiated lesions showing a more conspicuous staining of basement membrane glycoprotein than less differentiated lesions.

CLINICAL SIGNIFICANCE

An understanding of how the extracellular matrix influences tumor development and invasion is fundamental in the development of new prognostic indicators and treatment strategies for oral squamous cell carcinoma..

Immunohistochemical expression of basement membrane proteins of verrucous carcinoma of the oral mucosa

Squamous cell carcinoma (SCC) of the oral cavity is an extremely invasive tumour of stratified squamous epithelium that spreads throughout degradation of the basement membrane (BM) and extra-cellular matrix. Oral verrucous carcinoma (VC) is a rare low-grade variant of oral SCC that penetrates into the subepithelial connective tissue. It also has a different clinical behaviour from classical oral SCC. We investigated the immunohistochemical expression of laminin, laminin-5, collagen IV and fibronectin in VC, severe epithelial dysplasia (SED) and SCC in order to analyse if the pattern of these molecules expression contributes to the differences in the biological behaviour of these diseases. The staining pattern of laminin was less intensive in SCC compared with SED and VC, and collagen IV expression was increased in VC compared with SED. Discontinuities of laminin, collagen IV and fibronectin were more evident in SED than in VC. This study indicates that VC has a biological behaviour different from SED or SCC, observable by immunohistochemistry in the BM zone.

Distribution of basement membrane in supraglottic carcinoma

The object of this study was to assess the distribution of basement membrane in supraglottic squamous cell carcinomas. Expression of type IV collagen was detected by immunohistochemistry in resected supraglottic squamous cell carcinomas, and the correlation was examined between expression of type IV collagen and clinicopathological factors and cervical lymph node metastasis of supraglottic squamous cell carcinomas patients. An intact, continuous basement membrane was found in 17 cases (42.5%), while partial or widespread loss of the basement membrane was detected in the other 23 cases (57.5%). Heavily defective basement membrane was much more frequently observed in cases with poor histological differentiation (P < 0.05). Cases with BM destruction were more likely to be accompanied by cervical lymph node metastasis (P < 0.05). These data suggest that assessing the distribution pattern of basement membrane may be helpful in evaluating the malignancy grading of supraglottic squamous cell carcinomas and the potential occurrence of cervical lymph node metastasis.

Molecular mechanisms of head and neck cancer

Despite advances in understanding the underlying genetics, squamous cell carcinoma of the head and neck (SCCHN) remains a major health risk and one of the leading causes of mortality in the world. Current standards of treatment have significantly improved long-term survival rates of patients, but second tumors and metastases still remain the most frequent cause of high mortality in SCCHN patients. A better understanding of the underlying genetic mechanisms of SCCHN tumorigenesis will help in developing better diagnostics and, hence, better cures. In this article we will briefly outline the current state of diagnostics and treatment and our understanding of the molecular causes of SCCHN.

Targeting a tumor-specific laminin domain critical for human carcinogenesis

Laminin-332 is critical for squamous cell carcinoma (SCC) tumorigenesis, but targeting it for cancer therapy has been unachievable due to key role of laminin-332 in promoting tissue integrity. Here, we show that a portion of laminin-332, termed G45, which is proteolytically removed and absent in normal tissues, is prominently expressed in most human SCC tumors and plays an important role in human SCC tumorigenesis. Primary human keratinocytes lacking G45 (DeltaG45) showed alterations of basal receptor organization, impaired matrix deposition, and increased migration. After SCC transformation, the absence of G45 domain in DeltaG45 cells was associated with deficient extracellular signal-regulated kinase and phosphotidylinositol 3-kinase (PI3K) pathway activation, impaired invasion, deficient metalloproteinase activity, and absent tumorgenicity in vivo. Expression of G45 or activated PI3K subunit in DeltaG45 cells reversed these abnormalities. G45 antibody treatment induced SCC tumor apoptosis, decreased SCC tumor proliferation, and markedly impaired human SCC tumorigenesis in vivo without affecting normal tissue adhesion. These results show a remarkable selectivity of expression and function for laminin-332 G45 in human SCC tumorigenesis and implicate it as a specific target for anticancer therapy.

Distinguishing Pseudoepitheliomatous Hyperplasia From Squamous Cell Carcinoma in Mucosal Biopsy Specimens From the Head and Neck

Context.—The differentiation of pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma is a difficult and frequently encountered distinction, especially in biopsy specimens from head and neck mucosa. The problem is compounded by inflamed and often poorly oriented tissue sections.

Objective.—To distinguish pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma, utilizing a panel of antibodies to various epithelial and stromal elements (p53, matrix metalloproteinase 1, E-cadherin, and collagen IV) that has been shown to be useful in differentiating intestinal adenomas with invasive adenocarcinoma from displaced adenomatous epithelium.

Design.—Thirty-three archival specimens (16 squamous cell carcinoma [12 with invasion and 4 with microinvasion] and 17 pseudoepitheliomatous hyperplasia) from head and neck mucosal locations were immunostained and examined by the authors.

Results.—We found increased nuclear staining of the invasive tumor cells with p53. There was decreased staining within invasive tumor nests with E-cadherin. There was highly significant increased staining within tumor cells and adjacent stroma with matrix metalloproteinase 1 (P &lt; .001). The only antibody in our panel that did not show a reliable staining pattern was collagen IV. It appeared fragmented in benign inflamed and malignant areas and therefore was not useful.

Conclusions.—p53, matrix metalloproteinase 1, and E-cadherin showed significant staining trends independent of inflammation and suboptimal tissue orientation. Although a properly oriented hematoxylin-eosin–stained section was our gold standard, we found this immunoperoxidase panel useful as a diagnostic adjunct in difficult cases.

Evaluation of basement membrane status in aggressive skin carcinomas with skull base invasion: a case-control study

Some skin carcinomas may be very aggressive. Breached of basement membrane (BM) has been in some situations associated with tumor aggressiveness. In this study, the status of BM in invasion was evaluated in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) with skull base invasion, and it was compared with tumor's good outcome. Integrity or breached of BM was visualized using immunohistochemistry technique with anti-type IV collagen antibody. The pattern of BM was classified as intact, breached, or absent in 24 BCCs and 11 SCCs with skull base invasion. Control group (good outcome) included 23 BCCs and 10 SCCs. Breached BM and absence of BM were respectively noted in 33.33% and 45.83% of BCCs with skull base invasion, compared with 8.33% and 17.395% in the control group ( P < .001). Regarding SCCs, ruptured and absent BMs were, respectively, noted in 36.36% and 63.64% of BCCs with skull base invasion, compared with 30% and 30% in the control group ( P = .075). In this study, destruction of BM was significantly more common in BCCs with skull base invasion, in comparison with those with good outcome. In SCC, this difference was not statistically significant.

Effect of induction chemotherapy on changes of laminin and syndecan expression in oral squamous cell carcinomas: a prospective, randomized, clinicopathologic and immunohistochemical study

Sixty patients with tumors of the floor of the mouth or of the tongue (T2N0-1-2M0) were randomized into three treatment groups. The first two groups participated in low-dose inductive chemotherapy, surgery, and then radiotherapy, whereas the third control group underwent only surgery and radiotherapy. In all three groups, studies were made of the stage, grade, sex, localization, extents of expression of the pretreatment laminin and syndecan-1 and the cancer specific survival rate, and the correlations among these. The response to neoadjuvant chemotherapy was assessed by means of a method that we developed, involving measurement of the degree of histologic regression observed in response to chemotherapy. Immunohistochemical methods were applied to investigate the changes in degree of expression of laminin and syndecan-1 in response to the medication and their correlations with the survival. As concerns the overall tumorfree survival rate, a significant difference was not found between the two chemotherapeutic groups. However, there was a significant difference between the survival indices of those who participated in cytostatic treatment (70%) and the control group (40%). In the clinical and immunohistochemical examinations, the initial laminin and syndecan-1 levels obtained from biopsy samples could be used as prognostic factors. Our model measuring the extent of histologic regression clearly demonstrated that the survival indices of the patients who responded to the neoadjuvant cytostatic treatment with adequate tissue regression were better than those of the patients who responded to the treatment to only a decreased extent or not at all. The changes in the expressions of laminin and syndecan-1 in response to cystostatic treatment proved to be important predictive factors. The increase or stagnation of these clearly forecast a good prognosis, whereas their decrease was a definite indication of poor prognosis.

Calcium-induced Matrix Metalloproteinase 9 Gene Expression Is Differentially Regulated by ERK1/2 and p38 MAPK in Oral Keratinocytes and Oral Squamous Cell Carcinoma

Matrix metalloproteinases (MMPs) play an important role in the invasive behavior of a number of cancers including oral squamous cell cancer (OSCC), and increased expression of MMP-9 is correlated with invasive and metastatic OSCC. Because calcium is an important regulator of keratinocyte function, the effect of modulating extracellular calcium on MMP-9 expression in OSCC cell lines was evaluated. Increasing extracellular calcium induced a dose-dependent increase in MMP-9 expression in immortalized normal and premalignant oral keratinocytes, but not in two highly invasive OSCC cell lines. Differential activation of MAPK signaling was also induced by calcium. p38 MAPK activity was down-regulated, whereas ERK1/2 activity was enhanced. Pharmacologic inhibition of p38 MAPK activity or expression of a catalytically inactive mutant of the upstream kinase MAPK kinase 3 (MKK3) increased the calcium induced MMP-9 gene expression, demonstrating that p38 MAPK activity negatively regulated this process. Interestingly blocking p38 MAPK activity enhanced ERK1/2 phosphorylation, suggesting reciprocal regulation between the ERK1/2 and p38 MAPK pathways. Together these data support a model wherein calcium-induced MMP-9 expression is differentially regulated by the ERK1/2 and p38 MAPK pathways in oral keratinocytes, and the data suggest that a loss of this regulatory mechanism accompanies malignant transformation of the oral epithelium.

Laminin-gamma2 overexpression in head-and-neck squamous cell carcinoma

To identify molecular markers for the progression of head-and-neck squamous cell carcinoma (HNSCC), we used RNA arbitrarily primed (RAP) PCR to determine the qualitative and quantitative differences in gene expression between normal epithelial cells, those derived from dysplastic oral mucosa and invasive and metastatic HNSCC. Three differentially expressed DNA fragments (RAP20, RAP21, RAP26) that were upregulated in a tumor cell line (T45) were identified as being regions of the gamma2 subunit of human laminin-5. Northern blot analysis of total cellular RNA revealed overexpression of these transcripts in 6 of 7 HNSCC cell lines compared with normal epidermal keratinocytes. In contrast, no differences were observed in HeLa (cervical carcinoma) or HCT116 (colon carcinoma) cells. Immunostaining of HNSCC cells derived from primary (HN4) and metastatic (HN12) tumors indicated elevated levels of endogenous laminin-gamma2 protein. Furthermore, HNSCC tissues demonstrated strong laminin-gamma2 staining, particularly in the peripheral basaloid cells of tumor islands at the invasion front. In contrast, only minimal staining of laminin-gamma2 was detected in basal cells of the normal epithelium. The data indicate that laminin-gamma2 is frequently overexpressed in HNSCCs and derivative cell lines and that its overexpression is likely to be useful as a marker of head-and-neck squamous malignancy.

The levels of expression of galectin-1, galectin-3, and the Thomsen-Friedenreich antigen and their binding sites decrease as clinical aggressiveness increases in head and neck cancers

BACKGROUND

The aim of this study was to investigate whether an increase in malignancy level is accompanied by significant modifications of the expression of galectin-1, galectin-3, and Thomsen-Friedenreich antigen (T antigen) as well as the expression of binding sites for these three markers in head and neck squamous cell carcinomas (HNSCCs).

METHODS

Immunohistochemical and glycohistochemical staining reactions were carried out with antibodies, labeled lectins, and a custom-made neoglycoprotein on the basis of histologic slides from a retrospective series of 40 normal and 75 HNSCC formalin fixed, paraffin embedded tissues, and were quantitatively described with the aid of computer-assisted microscopy.

RESULTS

Whatever the histologic type, the epithelial tissues in HNSCC exhibited very significantly (P < 0.01 to P < 0. 0001) lower amounts of galectin-1, galectin-3, and T antigen and their respective binding sites than their corresponding normal counterparts. The tumors of the larynx differed very significantly (P < 0.0001 to P < 0.000001) from all the other tumor types. A loss of differentiation in the HNSCCs is accompanied first by the loss of expression of galectin-3 and galectin-3-reactive sites and then by that of the T antigen and its binding site(s). The opposite feature was observed when the parameters associated with the TNM classification were taken into account. The negative lymph node HNSCCs could be distinguished (P = 0.02) from the positive lymph node HNSCCs on the basis of a loss of galectin-3 expression. The modifications occurring in the extent of expression of galectin-1 and galectin-1-reactive sites were relatively marginal in comparison with those observed for galectin-3-dependent and T- antigen-dependent staining.

CONCLUSIONS

The decrease in the extent of expression of galectin-3 and galectin-3-reactive sites, T antigen and T antigen-binding sites, and, to a lesser extent, galectin-1 and galectin-1-reactive sites correlates significantly with an increasing level of clinically detectable HNSCC aggressiveness.

Expression of MMPS, MT-MMP, and TIMPs in squamous cell carcinoma of the oral cavity: correlations with tumor invasion and metastasis

BACKGROUND

Matrix metalloproteinases (MMPs) that degrade the extracellular matrices (ECMs) have been thought to play an important role in both the invasion and metastasis of tumors. However, the detailed role of MMPs and TIMPs (tissue inhibitors of MMP) on the biological behavior of tumor cells has yet to be elucidated in vivo. The aim of the present study was thus to determine whether expression of MMPs on tumor cells is associated with such clinicopathological features as the invasive and metastatic potential.

MATERIALS AND METHODS

This study included 96 cases of primary oral squamous cell carcinoma (OSCC), of which 38 cases showed lymph node metastases. The relationship between the expression of MMPs and the staining of ECMs, the mode of tumor invasion, nodal involvement, and expression of TIMPs was immunohistochemically examined.

RESULTS

First of all, a decrease in the staining of ECMs was observed in cases with an increased expression of MMP-1, -2, and -9. The association between the expression of MMPs and the loss of ECMs was thus found to be statistically significant. Secondly, in both invasive and metastatic cases, a marked expression of MMP-1, -2, -3, -9 and MT1-MMP was frequently observed. The association of the expression of MMPs both with the mode of tumor invasion and nodal involvement was thus found to be statistically significant. Thirdly, TIMP-2 was thus found not to significantly decrease in metastatic cases, while TIMP-1 expression significantly increased in metastatic cases.

CONCLUSION

These results suggest that tumor progression is dependent on the ability of tumor cells to degrade ECMs, while the metastasis of tumors is regulated by many types of MMPs, and the overproduction of MMPs therefore appears to be more important for metastasis than the production of TIMPs in vivo.

Loss of basement membrane components laminin and type IV collagen parallels the progression of oral epithelial neoplasia

AIMS

To determine the immunohistochemical localization of basement membrane components laminin and type IV collagen in premalignant and malignant lesions of the oral epithelium.

METHODS AND RESULTS

Formalin-fixed tissue sections of 12 epithelial hyperplasias with no dysplasia and 30 dysplasias, clinically diagnosed as leukoplakia and/or erythroplakia, as well as 50 invasive squamous cell carcinomas, were stained with mouse monoclonal antibodies to human laminin and type IV collagen. Statistical analysis showed that there was a linear trend for discontinuous distribution of laminin from epithelial hyperplasia to epithelial dysplasia and invasive squamous cell carcinoma (P < 0.001). Laminin staining showed a linear trend for discontinuity with increasing grade of dysplasia (P < 0.05) and was more frequently discontinuous in areas of deep tumour invasion than in central or superficial areas (P < 0.05). Brush-shaped thickening and reduplication of the basement membrane were also identified.

CONCLUSIONS

Alterations in the distribution of laminin and type IV collagen in oral premalignant and malignant lesions indicate that the loss of continuity of the subepithelial basement membrane parallels the progression of the neoplastic transformation process in oral epithelium.

Defective basement membrane in laryngeal carcinomas with heterogeneous loss of distinct components

In this study, we evaluated immunohistochemically the composition of the tumor-associated epithelial basement membrane (BM) in a series of 66 laryngeal squamous cell carcinomas (SCC) and compared these results with those from 10 cases with laryngeal dysplasia and five cases with normal mucosa (controls). The major BM components collagen IV and VII, laminin-1, perlecan (heparan sulfate proteoglycan), and fibronectin were evaluated. The extent of the retained BM material was quantified by semiautomated morphometry. A subsequent statistical analysis correlated the immunohistochemical findings with the histopathologically evaluated degree of tumor cell differentiation. In our series, we observed a distinct correlation between the degree of tumor cell differentiation and the amount of retained BM material. The loss of BM affected the various components differently, with a more extensive loss of collagen VII even in highly differentiated tumors and a progressive loss of collagen IV immunostaining with decreasing tumor cell differentiation. With respect to the other BM components, a stepwise loss of BM material also was seen with decreasing degree of the tumor cell differentiation. This loss, however was not at a statistically significant level, so these parameters did not show further statistically relevant data. In dysplastic lesions (regardless of the degree of dysplasia), focal BM disruptions were seen that affected the various BM components to a very similar extent. Our observations provide evidence that laryngeal carcinomas show a progressive loss of BM material along with decreasing tumor cell differentiation. This loss of BM, however, affects the various BM components differently. This indicates a dysregulation of the BM, either induced by uncoordinated neosynthesis or selectively enhanced degradation by proteases or both. Finally, the BM analysis may provide information on the biological course of the tumors. The loss of collagen VII may serve as a marker for "early" invasive tumor growth, whereas the amount of collagen IV provides significant information on the loss of tumor cell differentiation.

The prognosis of oral mucosal squamous cell carcinomas: a comparison of clinical and histopathological grading and of laminin and type IV collagen staining

Changes in the distribution of basement membrane components have been described in dysplastic lesions and in oral mucosal squamous cell carcinomas (OMSCC). The purpose of this study was to determine if these changes were related to pathological grade and if so, whether this had prognostic implications. Fifty formalin-fixed, paraffin-embedded specimens of OMSCC, with five or more years clinical follow-up, were studied using an immunoperoxidase technique for the detection of the basement membrane components, laminin and type IV collagen. The immunoreactivity of each component was evaluated and semiquantitatively scored as minimal, moderate or extensive and the results compared with the tumour size, node involvement and metastasis (TNM) clinical staging system and histopathological features. OMSCC were characterized by minimal or moderate staining with small islands of neoplastic cells frequently lacking staining for laminin and type IV collagen. Deposition of these components decreased with increased histopathological grade and absence of staining was more commonly associated with a poor prognosis. In particular the pattern of type IV collagen staining frequently differed from laminin staining. Neither of these parameters offered an advantage over TNM clinical staging with regard to prognosis. It was concluded that variations in laminin and type IV collagen immunoreactivity occurred in OMSCC and that high histopathological grade tumours with considerably diminished staining with anti-laminin and anti-type IV collagen carried a poor prognosis.

Morphometric evidence that epithelial basement membrane breaks are a feature of both squamous and basal cell carcinomas of the skin

There have been reports that squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) are surrounded by continuous epithelial basement membranes (EBMs). This argues against the hypothesis that EBM breaks are required for tumour invasion. We have used morphometric techniques to re-examine the evidence for SCCs and BCCs as objectively as possible. We assessed sections stained for type-IV collagen from 12 SCCs, 14 keratoacanthomas (KAs), 9 morphoeic BCCs, 10 nodular BCCs and 7 superficial multifocal BCCs. In the centre of these tumours, the EBM was generally more continuous than at the periphery, and this difference was statistically significant for SCCs, KAs and morphoeic BCCs (p < 0.01 in all). By considering central and peripheral tumour regions separately, a significant difference was seen between SCCs and the difficult to distinguish benign tumour KA. In the centre of the KAs, EBM was significantly more continuous than than in SCCs (p = 0.0029), which may suggest new ways of distinguishing these lesions. All of the SCCs and morphoeic BCCs examined showed clear evidence of EBM breaks, but some nodular BCCs did not. As nodular BCCs show an expansile growth pattern without typical histological features of tumour invasion, we suggest that these tumours may be at a pre-malignant stage. In general, our findings are consistent with the hypothesis that EBM breaks are required for tumour invasion.

Basement membrane components of bronchial epithelium in humans suffering from chronic nonspecific lung diseases

Collagen IV and laminin are important constituents of the basement membrane (BM). By use of immunocytochemistry we examined the occurrence and distribution of these two components in the BM beneath normal, mucoid and metaplastic epithelium of large bronchi in 22 adults suffering from chronic nonspecific lung diseases. Both collagen IV and laminin were expressed as a thin and continuous layer beneath the epithelium in most tissue specimens with normal epithelium. In a few specimens the layer showed interruptions with a patchy distribution of the immunoreactivity. Three patterns of distribution of BM components were found under the metaplastic epithelium. Total absence of immunoreactive collagen IV and laminin was the most common variant. Weak and scarce staining for both proteins in the BM characterized the second pattern. The third variant showed strong collagen IV immunoreactivity but lack of laminin. The BM beneath the mucoid epithelium was characterized by irregular distribution of collagen IV and laminin. We suggest that the occurrence and distributional pattern of the BM components are related to the type of overlying epithelium and connected with an altered synthesis of these components.

Alterations in expression of basement membrane proteins during tumour progression in oral mucosa

Expression of three basement membrane proteins--collagen IV, laminin and fibronectin--was studied in normal, hyperplastic, dysplastic and neoplastic conditions of the oral mucosa using immunohistochemistry. Collagen IV and laminin exhibited similar staining patterns, while fibronectin showed a different pattern of expression. The expression of collagen IV and laminin also demonstrated an inverse correlation between staining intensity, thickness and basement membrane continuity in various stages of tumour progression. In contrast to the continuous and intense staining of basement membrane in normal oral mucosa with collagen IV and laminin antibodies, severe dysplasia and carcinoma exhibited discontinuous, thin and weakly stained basement membrane. The expression of fibronectin showed a direct correlation with extent of tumour progression. In normal mucosa, expression of fibronectin was almost absent, whereas in carcinoma intense expression of fibronectin was evident in the basement membrane and basal cells. These results emphasize the value of basement membrane proteins as biological markers for assessing oral carcinogenesis.

Immunohistologic distribution of basement membrane in oral squamous cell carcinoma

The distribution pattern of the basement membrane (BM) around tumor cells was determined in 72 oral squamous cell carcinomas by immunohistochemical staining with antibodies against human type IV collagen, laminin, and heparan sulfate proteoglycan. An intact continuous BM was found in 29 cases, whereas partial or widespread loss of the BM was detected in the other 43 cases (59.7%). Statistical analysis showed that the degree of BM loss was correlated with the degree of differentiation of tumor cells, but not with tumor size, and, most significantly, with the mode of cancer invasion and the incidence of lymph node metastasis. Carcinoma with a well-defined tumor-stromal boundary generally expressed an intact continuous BM. In contrast, the majority of diffusely invasive carcinomas lacked a continuous BM. Carcinomas with a widespread loss of BM structures showed a high frequency of regional lymph node metastasis (16 of 18 cases, 88.9%).

Loss of alpha 6 and beta 4 integrin subunits coincides with loss of basement membrane components in oral squamous cell carcinomas

In oral squamous cell carcinomas, focal or extensive loss of basement membrane components and of integrins has been reported. The purpose of this study was to investigate whether those regions of the tumour-connective tissue interface which lack laminin and type IV collagen coincide with areas of loss of the alpha 6 and beta 4 integrin subunits on basal keratinocytes. Out of a total of 15 poor and moderately or well differentiated squamous cell carcinomas, all showed some loss or fragmentation of basement membrane proteins and in 12 the loss was coincident with loss of alpha 6 and/or beta 4. In three cases, there was loss of basal integrin expression in areas where the basement membrane remained intact. These results provide further evidence that loss of integrins may play an important role in tumour progression and prompt us to speculate about the sequence of events leading to tumour invasion.

Clinical significance of laminin deposition and T-cell infiltration in oral cancer

Biopsied specimens from 55 patients with squamous cell carcinoma (SCC) of the oral cavity were examined immunohistopathologically as to the clinical significance of basement membrane (BM) deposition and T-cell infiltration at the tumor-stromal border using monoclonal anti-laminin and anti-CD3 antibodies. According to the immunoreactivity, all specimens could be divided into three groups: group A, a continuous linear pattern of positive staining for BM around tumor nests; group B, an alteration of BM deposition around tumor nests with T cell infiltration into those tumor nests; and group C, an alteration of BM deposition around tumor nests without T cell infiltration into those tumor nests. These groups were correlated with clinical manifestations, such as tumor size, tumor regression rate with induction chemotherapy, and regional lymph node metastatic rate. In these groups, tumors classified as group C showed a trend toward resistance to chemotherapy and high metastatic characteristics. Tumors classified as group B, which showed the same alteration of BM deposition as a result of T cell infiltration into the tumor nests, showed a sufficient tumor regression rate with chemotherapy. The visualization of the staining for BM laminin and T cells in oral SCC appeared not only to increase our understanding of the biologic and clinical behavior of individual tumors, but could be a prognostic indicator.

Premalignant lesions of the upper aerodigestive tract: biomarkers of genetic alterations, proliferation, and differentiation

The normal distribution of cell division in squamous mucosa is in the basal or adjacent suprabasal cell layers. Migration of cells toward the epithelial surface results in cell differentiation, most often expressed by high molecular weight keratin intermediate filaments and components of the cornified envelope, including "involucrin." These latter expressions of terminal differentiation are common in keratinizing dysplasia and invasive squamous cell carcinomas. However, they are less common in the non-keratinizing dysplasias, which fail to express evidence of epithelial maturation. Cell proliferation occurs in or near the basal layer in normal or reactive/reversible hyperplasias. In dysplasia (both keratinizing and non-keratinizing), cell proliferation is observed at all levels of the epithelium. Concomitant with these abnormalities in proliferation and differentiation are nuclear changes characterized by large hyperchromatic nuclei. The enlarged nuclei reflect increased DNA content, as documented by flow cytometry and image analysis techniques. DNA aneuploidy represents a spectrum of genomic alterations reflecting steps toward the progression to invasive carcinoma, which for the most part, have not yet been identified.

Immunohistochemical localization of basement membrane type VII collagen and laminin in neoplasms of the head and neck

The distribution pattern of the basement membrane components type VII collagen and laminin, was studied immunohistochemically in normal human head and neck tissues and in a series of benign and malignant tumours from the same site. Using monoclonal antibodies, a basement membrane containing type VII collagen and laminin could be demonstrated beneath the epithelial cell layer in 16 normal head and neck tissues from different localizations. Unlike type VII collagen, laminin was also abundantly present around blood vessels and muscle fibres. With respect to 42 squamous cell carcinomas studied, type VII collagen and laminin were present in basement membranes surrounding small and large tumour fields, independent of the tumour grade. Type VII collagen was demonstrated in the cytoplasm of tumour cells in 36% of the cases, while the antibody to laminin displayed a basement membrane staining pattern mainly. Both antibodies showed a staining gradient in more than half of the cases, with strong staining in the centre of the tumour and weakening of the staining towards the tumour periphery. In a series of 22 salivary gland tumours consisting of 19 pleomorphic adenomas and three adenoid cystic carcinomas, the distribution pattern of type VII collagen and laminin was very heterogeneous. Laminin was present in 17 and type VII collagen in 10 of 19 cases of pleomorphic adenoma, mostly scattered throughout the tumour fields. In the tumours positive for type VII collagen areas with little or no positivity were also found. A correlation between type VII collagen positivity and the presence of basal cell keratin 14 positivity was noticed in the majority of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of the basal lamina in xenografted human carcinomas: an ultrastructural and immunohistochemical study

The development of the basal lamina (BL), the key structure of the basement membrane (BM), was investigated in three xenografted human carcinomas of the sigmoid colon (CA 1), the lung (L 261), and the hypopharynx (H-Stg 1) following heterotransplantation to athymic mice. The study involved the use of electron microscopy and indirect immunofluorescence techniques employing highly specific antibodies against the intrinsic BL components, heparan sulfate proteoglycan, laminin and type-IV collagen. Following transplantation, the extracellular matrix material of the transplanted tumors decomposed and was phagocytozed by invading macrophages within 1 to 2 days. During this stage, no specific binding of the applied antibodies to BL components could be detected within the xenografts. Following the ingrowth of host-derived connective tissue between days 2 to 6, small fluorescence-positive granules appeared within the cytoplasm and around those tumor cells that were located close to the invaded strands of connective tissue. Ultrastructurally, typical secretory granules were detectable in the cytoplasm of many xenografted carcinoma cells. Thereafter, a tannic acid-positive, patchy material appeared in the extracellular space of CA 1 and L 261 and aggregated to form small fragments of a discontinuous BL. In the H-Stg 1 xenografts, this material assembled to form continuous mono-, bi- and multi-layered structures. Large amounts of excess BL material remained accumulated in the L 261 and H-Stg 1 xenografts until the end of the observation period (day 24). These findings reveal that discontinuities of the BL occur independent of the active invasion processes of tumor cells, since xenografted human carcinomas neither grow invasively nor metastasize in nude mice. Moreover, they confirm that these discontinuities are not caused by a quantitatively insufficient production of BL material, but rather arise from qualitative imbalances of the composition of the synthesized BL material.

Assessment of invasion in breast lesions using antibodies to basement membrane components and myoepithelial cells

This paper describes immunostaining of consecutive sections from 15 cases of fibrocystic change of the breast (including 2 examples of intraductal papilloma), 4 ductal carcinomas-in-situ and 17 invasive carcinomas (4 tubular, 1 papillary, 2 lobular and 10 infiltrating ductal, NOS) with antisera to components of the basement membrane (BM), type IV collagen and laminin, and with the muscle antibodies actin and muscle-specific actin. A simple digestion technique was developed to improve the clarity of BM staining with these antibodies. The BM stains facilitated identification of small invasive foci through breaks in the BM in 2 of the cases which had been reported as pure intraductal carcinoma. Tubular carcinomas were surrounded by abnormal, fragmented, and focally discontinuous BM, a feature which could be used to distinguish this well-differentiated breast carcinoma sub-type from sclerosing adenosis, in which individual acini were invariably surrounded by a continuous BM. BM staining emphasized the fibrovascular core of intraductal papillomas, whereas the BM layer was absent in intraductal, cytologically malignant, papillary projections. Similarly, myoepithelial cells, stained with antisera to muscle actins, were identified in a continuous layer surrounding benign epithelial proliferations. These immunohistochemical staining techniques may thus assist the diagnostic histopathologist in differentiating between benign epithelial proliferations of the breast and well-differentiated invasive breast carcinoma, and in identifying foci of microinvasive carcinoma.

Distribution of basement membrane antigens in human esophageal lesions: an immunohistochemical study

The distribution of basement membrane components, type-IV collagen and laminin, was studied immunohistochemically in human samples of normal, hyperplastic, dysplastic and carcinomatous esophageal tissue. The expression of basement membrane components in normal, hyperplastic, and mildly and moderately dysplastic mucosa was characterized by a thick, continuous and linear staining pattern. In severe dysplasia and carcinoma in situ, the basement membrane was thinner and occasionally discontinuous. The distribution of basement membrane in invasive carcinomas varied greatly; well-differentiated, cohesive tumors had a basement membrane, however, poorly-differentiated tumors showing irregular cords, or individual cell infiltration, lacked this membrane at the tumor-stromal interface. Many moderately-differentiated tumors showed probable immature assembly of basement membrane components. The expression of basement membrane was also influenced by the extent of stromal inflammation. The absence or presence (staining pattern) of basement membrane components in esophageal squamous-cell carcinoma did not correlate with the survival rate, but did correlate with the histologic differentiation of epithelial organization.

Basement membrane components in normal, dysplastic, neoplastic laryngeal tissue and metastatic lymph nodes

The immunohistochemical localization of the basement membrane (BM) components laminin, type IV collagen and fibronectin was analyzed in normal, dysplastic and neoplastic laryngeal specimens. The distribution of these macromolecules was also investigated in metastatic lymph nodes. A regular and continuous staining for laminin and type IV collagen was present in normal and mild dysplastic epithelium (LIN I); interruptions and reduplications were more evident in severe dysplasia (LIN III), together with an increased positivity for fibronectin in the subepithelial connective tissue. In squamous cell carcinomas the distribution of BM components was related to the degree of cellular differentiation, with a decreased immunostaining being evident in moderately and poorly differentiated carcinomas. Furthermore, the positivity for laminin and type IV collagen was influenced by the pattern of neoplastic growth, being continuous around the "pushing" border and discontinuous where the neoplastic front had an "invading" appearance. Similar changes were present in cervical metastatic lymph nodes. These observations tend to support the theory that the neoplastic growth is a cyclic process, with BM component synthesis and reabsorbtion related to the shifts of cellular metabolism.

Distribution of epithelial antigens in the human uterine cervix: a review

Epithelial antigen immunostaining in the uterine cervix has been claimed to be helpful in the identification and classification of rare lesions, evaluation of basement membrane integrity, study of atypical condylomas, immunodetection of proliferating processes and early diagnosis of malignant transformation. The present review attempts to demonstrate the potential value of immunohistological techniques as a means of identifying normal and abnormal patterns of antigenic expression in cervical epithelium.