The molecular profiling of solid tumors by liquid biopsy: a position paper of the AIOM-SIAPEC-IAP-SIBioC-SIC-SIF Italian Scientific Societies.

The term liquid biopsy (LB) refers to the use of various biological fluids as a surrogate for neoplastic tissue to achieve information for diagnostic, prognostic and predictive purposes. In the current clinical practice, LB is used for the identification of driver mutations in circulating tumor DNA derived from both tumor tissue and circulating neoplastic cells. As suggested by a growing body of evidence, however, there are several clinical settings where biological samples other than tissue could be used in the routine practice to identify potentially predictive biomarkers of either response or resistance to targeted treatments. New applications are emerging as useful clinical tools, and other blood derivatives, such as circulating tumor cells, circulating tumor RNA, microRNAs, platelets, extracellular vesicles, as well as other biofluids such as urine and cerebrospinal fluid, may be adopted in the near future. Despite the evident advantages compared with tissue biopsy, LB still presents some limitations due to both biological and technological issues. In this context, the absence of harmonized procedures corresponds to an unmet clinical need, ultimately affecting the rapid implementation of LB in clinical practice. In this position paper, based on experts' opinions, the AIOM-SIAPEC-IAP-SIBIOC-SIF Italian Scientific Societies critically discuss the most relevant technical issues of LB, the current and emerging evidences, with the aim to optimizing the applications of LB in the clinical setting.

ReportFlow: an application for EEG visualization and reporting using cloud platform.

BACKGROUND: The cloud is a promising resource for data sharing and computing. It can optimize several legacy processes involving different units of a company or more companies. Recently, cloud technology applications are spreading out in the healthcare setting as well, allowing to cut down costs for physical infrastructures and staff movements. In a public environment the main challenge is to guarantee the patients' data protection. We describe a cloud-based system, named ReportFlow, developed with the aim to improve the process of reporting and delivering electroencephalograms. METHODS: We illustrate the functioning of this application through a use-case scenario occurring in an Italian hospital, and describe the corresponding key encryption and key management used for data security guarantee. We used the X2 test or the unpaired Student t test to perform pre-post comparisons of some indexes, in order to evaluate significant changes after the application of ReportFlow. RESULTS: The results obtained through the use of ReportFlow show a reduction of the time for exam reporting (t = 19.94; p < 0.001) and for its delivering (t = 14.95; p < 0.001), as well as an increase of the number of neurophysiologic examinations performed (about 20%), guaranteeing data integrity and security. Moreover, 68% of exam reports were delivered completely digitally. CONCLUSIONS: The application resulted to be an optimal solution to optimize the legacy process adopted in this scenario. The comparative pre-post analysis showed promising preliminary results of performance. Future directions will be the creation and release of certificates automatically.

Multidisciplinary model for hospital-territory integrated management of patient with bone fragility: primary and secondary prevention of fractures according to severity and complexity.

The aim of this study was to promote the construction of a real network and a shared diagnostic and therapeutic management model between hospitals and out-of-hospital healthcare services to capture as many patients with bone fragility as possible. Starting from the analysis of the clinical competences present in the province of Pavia, the bone specialists (BSs) organized some educational events involving both general practitioners (GPs) and hospital specialists. The Fracture Liaison Service (FLS) model, the revision of Note 79, the national plan for chronicity and the health reform of the Lombardy Regional Authority supported the structure of our model, in which the roles of clinicians are well defined and based on the complexity and severity of patients. In our method the GP has a central role as clinical manager, facilitating patient management and communication between the specialists and the BS. In January 2019, the Therapeutic Care Diagnostic Path (PDTA) shared between 2 bone specialists (BSs), 9 GPs, as reference treaters, and a multidisciplinary group of 25 specialists of the Province of Pavia was defined. The strategic directions of the two largest public hospitals in Pavia have supported the PDTA, which was validated by the quality departments of the hospitals themselves. Finally, sixty GPs belonging to the network have joined the PDTA. This model is the first example of integrated management between hospitals and out-of-hospital healthcare services for the primary and secondary prevention of fragility fractures (FF), where the GPs play a pivotal role as managers and supervisors to ensure proper care to chronic patients according to their levels of severity.

HER2 status in advanced gastric carcinoma: A retrospective multicentric analysis from Sicily.

According to the ToGA trial, HER2 has been shown to be predictive for the success of treatment with trastuzumab in advanced gastric cancer (AGC). A number of studies have analyzed HER-2/neu overexpression in gastric carcinoma and identified the rate of HER2 positivity to be markedly varied. To date, the prevalence of HER2 overexpression in Sicilian people with AGC is unknown. Therefore, in the present study, a retrospective immunohistochemical analysis of HER2 was performed in a cohort of 304 AGC samples that were obtained from the archives of 10 Sicilian anatomopathological diagnostic units in order to verify the positive rate of HER2-positive cases. Furthermore, the characteristics of histotype, grade, stage and Ki-67 expression were also analyzed. HER2 overexpression was encountered in 17.43% of all the gastric adenocarcinomas, which was consistent with the results that have been reported elsewhere in the literature. A progressive increase in HER2 overexpression was observed, from the poorly cohesive histotype to the tubular adenocarcinomas and gastric hepatoid adenocarcinomas. HER2 overexpression was significantly associated with a high grade, advanced stage and high Ki-67 labeling index. Further investigations performed jointly by pathologists and oncologists within the geographical area of the present study should confirm that the association of trastuzumab with chemotherapy results in an improvement of survival in patients with AGC.

Immunoexpression of lactoferrin in bone metastases and corresponding primary carcinomas.

Although the immunohistochemical presence of lactoferrin (LF) in pathological neoplastic bone and cartilage samples has previously been studied, no data concerning the distribution of LF in bone metastases of cancers that have originated from different organs are available at present. Consequently, using a monoclonal antibody, we have investigated the immunohistochemical LF pattern in 50 formalin-fixed and paraffin-embedded samples of human bone metastases and their corresponding primary carcinoma tumours (breast, 8; prostate, 4; kidney, 4; lung, 3; colon-rectum, 2 and uterus, 4). Quantification of LF immunoreactivity was performed using an intensity distribution (ID) score. LF immuno staining with a variable ID score was encountered in 11/25 (44%) metastatic lesions. In particular, the LF immunoreactivity was identified with a percentage ranging from 50 to 75% of bone metastases due to prostatic, renal, uterine and colorectal carcinomas; the positivity decreased in breast carcinomas (37.5%) and was completely absent in lung cancers. No differences in the LF-ID score were observed between primary and metastatic neoplastic localisations. Additionally, no correlations were identified between LF immunoexpression and the other parameters tested, including the age and gender of patients. Regardless of the mechanism of action of LF in human malignant tumours, we identified LF immunohistochemical reproducibility at primary and metastatic sites. Therefore, we hypothesise that the presence of LF in native neoplastic carcinomatous clones is maintained in secondary bone metastatic deposits.

Morphological and biomolecular characteristics of subcentimetric invasive breast carcinomas in Sicily: A multicentre retrospective study in relation to trastuzumab treatment.

Little information from clinical trials is available regarding the efficacy of trastuzumab treatment in subcentimetric breast carcinomas (BCs). The aim of this study was to verify the existence of correlations between HER2 and hormone receptor status, Ki67 values, grade, histotype and node involvement in a cohort of pT1a,b BCs from an area not widely covered by screening campaigns. A total of 410 pT1a,b BC formalin-fixed paraffin-embedded samples collected from eight Sicilian Anatomo-Pathological Units (APUs) were classified according to the WHO classification and tumour grading was established. Estrogen and progesterone receptor status, Ki67 labelling index and HER2 status were available. Relationships between immunohistochemical data and clinicopathological characteristics were investigated using the Chi-square test; the cohort was analysed with respect to pT1a and pT1b BC as well as to node status. Ductal infiltrating carcinoma was the prevalent histotype in the pT1a and pT1b stages; G2 was a more common tumour grade, with a range between 64.6% and 70% of pT1a and pT1b, respectively. Taking into consideration the lymph node involvement of pT1a,b BC, only 17.1% cases were node-positive without a relevant difference between pT1a and pT1b. No significant differences between pT1a and pT1b BC cases emerged in relation to Ki67 LI, hormone receptors and HER2 status. T1a,b BC cases were stratified by node involvement and a significant relationship was observed with grade as well as with HER2 status. A significant relationship for pT1a cases emerged only for tumour grade, while pT1b cases showed a significant correlation exclusively with HER2 status. Our data clearly support the operative guidelines of the National Comprehensive Cancer Network. Therefore, the combined treatment with trastuzumab plus chemotherapy should be administered only to patients with pT1b or larger BCs. In small HER2-positive pT1a or microinvasive BC, this therapy should be considered on a case-by-case basis, considering tumour grade as the first characteristic.

Hematopoietic progenitor cells (HPCs) in node-negative invasive breast carcinomas: Immunohistochemical analysis and clinico-pathological correlations.

Using immunohistochemistry, we investigated 603 negative lymph nodes from 51 patients affected by invasive breast cancer (BC) to recognize bone marrow-derived hematopoietic progenitor cells (HPCs). HPC aggregates, revealed by CD34, CD133, VEGFR1, and CD117 antisera, were determined by an intensity-distribution score (ID). Cases with an ID-score >3 at least for one marker were considered to strongly express HPCs. Twenty-five of 51 (49%) high expressor patients were identified by CD34 antiserum, while 24/51 (47.1%), 17/51 (33.3%), and 15/51 (29.4%) were identified by CD117, CD133, and VEGFR1, respectively. No significant relationships were found between HPCs status and histotype, tumor grade, stage, and hormone receptors, as determined at the moment of the first diagnosis. A significant correlation was recorded for Ki-67 values, as well as for death from invasive BC. No statistical significance was achieved regarding HER2 status, although a tendency toward a statistically significant P value was obtained. A significant relationship (P<0.001) was found between high expressors of HPC and progression of disease, documented by the development of distant metastases. An equivalent P value was ascertained for osseous localizations, with a lesser value in other metastatic sites. Regarding the appearance of distant metastases, the greatest efficiency value was obtained by CD133 (85.7%). Overall survival (OS) and distant metastases-free survival (DMFS) revealed a high statistical significance for HPC expression, Ki-67 values, and HER2 status. By multivariate analysis, HPC expression and Ki-67 values emerged as the higher independent prognostic variables in the analysis of DMFS and OS, respectively.

Prognostic impact of CD133 immunoexpression in node-negative invasive breast carcinomas.

BACKGROUND: Hematopoietic progenitor cells (HPCs) are able to prepare the site for incoming neoplastic cells. Among different markers of HPCs, which one should be considered the most efficient was investigated. PATIENTS AND METHODS: Five hundred and seventy-nine non-metastatic lymph nodes from 49 patients affected by invasive breast cancer were submitted to an immunohistochemical comparative analysis of hematopoietic (CD34), endothelial (CD133), mesenchymal (CD117) progenitors and vascular endothelial growth factor receptor 1 (VEGFR1, also known as Flt1). The cases with an intensity-distribution score >3 were considered as high HPC expressors. Survival univariate and multivariate analyses were performed. RESULTS: Fifteen out of the 49 patients were recorded as HPC high expressors based on the immunohistochemical VEGFR1 staining. A highly significant relationship was found between high HPC immunoexpression and the development of distant metastasis as well as the occurrence of bone localization (p<0.001). By univariate analysis, CD133 showed a highly significant value regarding metastatic localizations in the bone; by multivariate analysis, CD133 emerged as the only independent prognostic variable. CONCLUSION: CD133 expression shows a potential predictive role, thus representing a helpful tool for the management of breast cancer.

The expression of adiponectin receptors Adipo-R1 and Adipo-R2 is associated with an intestinal histotype and longer survival in gastric carcinoma.

BACKGROUND: Adiponectin (ApN) is a 30 kDa adipocytokine which mediates an antineoplastic effect after binding to its receptors, Adipo-R1 and Adipo-R2. The expression of these receptors has been documented in gastric cancer (GC) cell lines, but only a few data exist on their expression in GC neoplastic tissue. AIM: To investigate the expression of Adipo-R1 and Adipo-R2 in a series of surgically resected GCs and to assess its association with various tumour clinicopathological characteristics as well as with patient survival. METHODS: Forty-nine surgically resected GCs were submitted to immunohistochemical assays for Adipo-R1, Adipo-R2 and ApN. RESULTS: Adipo-R1 and Adipo-R2 immunoexpression was found in 22/49 GCs and in intestinal metaplasia areas near the tumours, whereas only slight immunoreactivity for these proteins was found in adjacent normal gastric epithelium. No ApN expression was encountered in any of the cases analysed. Adipo-R1/Adipo-R2 expression was significantly associated with an intestinal histotype of the tumours and with longer overall survival of the patients. CONCLUSIONS: Intestinal-type GCs often express Adipo-R1/R2 in association with a better prognosis. The presence of these receptors could be exploited for novel anticancer therapies based on ApN addition in GC.

Immunohistochemical localization and functional characterization of somatostatin receptor subtypes in a corticotropin releasing hormone- secreting adrenal phaeochromocytoma: review of the literature and report of a case.

Somastostatin receptors are frequently expressed in phaeochromocytoma but data on somatostatin receptor subtyping are scanty and the functional response to the somatostatin analogue octretide is still debated.We report an unusual case of pheochro-mocytoma,causing ectopic Cushing's syndrome due to CRH production by the tumour cells, in a 50-yr-old woman. Abdominal computed tomography revealed an inhomogeneous,9-cm mass in the right adrenal gland,and [111In-DTPA0] octreotide scintigraphy showed an abnormal uptake of the radiotracer in the right perirenal region,corresponding to the adrenal mass.The patient underwent laparoscopic surgery and formalin-fixed and paraffin embedded samples were studied. The tumour was extensively characterized by immunohistochemistry and somatostatin receptor (SSTRs) subtypes expression was analyzed.Histological and immunohistochemical examination of the surgical specimens displayed a typical pheochromocytoma,which was found to be immunoreative to S-100, chromogranin A and neurofilaments. Immunostaining for SSTR subtypes showed a positive reaction for SSTR1, SSTR2A, SSTR2B, antisera on tumour cells. The intense and diffuse immunostaining for corticotropin releasing hormone (CRH) antiserum indicated that Cushing's disease was dependent on CRH overproduction by the pheochromocytoma,in which no immunostaining for adrenocorticotropic hormone was found. Our report confirms the heterogeneity of the pattern of SSTR expression in pheochromocytomas,and provide further evidence for functional SSTR subtype SSTR2a in a subgroup of pheochromocytomas,suggesting that these tumours may represent potential target for octreotide treatment.

Immunohistochemical localization and functional characterization of somatostatin receptor subtypes in a corticotropin releasing hormone-secreting adrenal phaeochromocytoma: review of the literature and report of a case.

Somastostatin receptors are frequently expressed in phaeochromocytoma but data on somatostatin receptor subtyping are scanty and the functional response to the somatostatin analogue octretide is still debated.We report an unusual case of pheochromocytoma, causing ectopic Cushing's syndrome due to CRH production by the tumour cells, in a 50-yr-old woman. Abdominal computed tomography revealed an inhomogeneous, 9-cm mass in the right adrenal gland, and [111In-DTPA0] octreotide scintigraphy showed an abnormal uptake of the radiotracer in the right perirenal region, corresponding to the adrenal mass. The patient underwent laparoscopic surgery and formalin-fixed and paraffin-embedded samples were studied. The tumour was extensively characterized by immunohistochemistry and somatostatin receptor (SSTRs) subtypes expression was analyzed. Histological and immunohistochemical examination of the surgical specimens displayed a typical pheochromocytoma, which was found to be immunoreative to S-100, chromogranin A and neurofilaments. Immunostaining for SSTR subtypes showed a positive reaction for SSTR1, SSTR2A, SSTR2B, antisera on tumour cells. The intense and diffuse immunostaining for corticotropin releasing hormone (CRH) antiserum indicated that Cushing's disease was dependent on CRH overproduction by the pheochromocytoma, in which no immunostaining for adrenocorticotropic hormone was found. Our report confirms the heterogeneity of the pattern of SSTR expression in pheochromocytomas, and provide further evidence for functional SSTR subtype SSTR2a in a subgroup of pheochromocytomas, suggesting that these tumours may represent potential target for octreotide treatment.

Caveolin-1 immuno-expression in human gastric cancer: histopathogenetic hypotheses.

The immunohistochemical expression of caveolin-1 (cav-1) was evaluated in a series of gastric carcinomas (GC) and in the adjacent normal gastric mucosa. Cav-1 immuno-expression was found in most GC (94%) with a significantly higher amount in the Lauren intestinal type in comparison to the diffuse-type carcinomas. Interestingly, gastric intestinal metaplasia as well as the cells at the base and neck of gastric pits within all fundic mucosal fragments showed an evident cav-1 immuno-staining, suggesting a histogenetic derivation of these lesions from the trans-differentiation of chief cells or from a cryptic progenitor population at the base of fundic glands, as recently hypothesized by other authors. The absence of significant correlations between cav-1 immuno-expression and the other clinico-pathological parameters, such as the stage of disease or the patients overall survival, indicates that the role of cav-1 in GC is neither stage-specific nor related to prognosis.

Actinic keratosis associated with squamous and basal cell carcinomas: an evaluation of neoplastic progression by a standardized AgNOR analysis.

In an attempt to investigate the neoplastic progression in different stages of actinic keratosis (AK), a standardized AgNOR analysis was performed in 94 cases of AK, 35 of which were associated with squamous cell carcinoma (SCC) or basal cell carcinoma (BCC), and in 31 cases of SCC and 22 cases of BCC. The cases were subdivided into low- and high-AgNOR-expressing (AgNOR status) AK by using the mean area of AgNORs per cell (NORA) value (3.996 micro(2)) as the cut-off. In AK samples, a progressive increase of the mean NORA value from Stage I to Stage IV was encountered. In addition, a significantly higher mean NORA value was found in the AK cases associated with SCC, in comparison to those without SCC; by contrast, no significant differences in the mean NORA value were noted between AK cases with or without BCC. A highly significant association between a high AgNOR quantity and the coexistence of SCC was encountered in AK; no association was appreciable between the AgNOR quantity and the co-occurrence of BCC. Moreover, when the co-existence of SCC in AK was considered as the reference point, the AK cases associated with SCC mostly (95.5%) presented a high AgNOR quantity (high sensitivity), but only 57.6% of cases without SCC displayed a low AgNOR quantity (low specificity). Additionally, our data document that the standardised AgNOR analysis represents a strong negative predictor for the association between SCC and AK. Indeed, a low AgNOR quantity mostly is associated with AK cases without SCC.

Caveolin-1 in meningiomas: expression and clinico-pathological correlations.

Caveolin-1 (Cav-1) protein has been documented in several neoplasms with a controversial role in cell proliferation, tumour development and progression. The aim of the present study was to investigate the Cav-1 immunohistochemical expression in human meningiomas. Sixty-two cases, classified as 11 meningothelial (17%), 12 transitional (19%), 5 fibrous (8%), 3 microcystic (5%), 3 secretory (5%), 1 clear cell (2%), 1 chordoid (2%) and 26 (42%) atypical meningiomas, were selected from our pathological files. Clinico-pathological data, including Ki-67 values and survival data were also available. Ten leptomeningeal samples were utilized as normal tissue control. For each case, a polyclonal antibody against Cav-1 was applied and an intensity distribution (ID) score was determined. The Cav-1 immunoexpression was found in 95% of meningiomas with a variable ID score, while only minimal, not uniform, reactivity was noted in non-neoplastic meninges. Of note, higher Cav-1 ID score was significantly correlated with tumour site, Simpson's grade, histological type, higher histologic grade, Ki-67 labelling index > or = 4% and clinical course. Kaplan-Meier curves demonstrated a significantly worse survival in patients with higher Cav-1 ID score, Ki-67 > or = 4% and 2-3 Simpson grade. Multivariate analysis indicated that only Ki-67 was an independent prognostic factor. Increased immunoexpression of the Cav-1 seems to be associated with the biological aggressiveness of meningiomas, reflecting a worse prognosis.

Quantity of AgNORs in gastric endocrine carcinoid tumours as a potential prognostic tool.

In order to assess if the quantity of silver-stained nucleolar organizer region (AgNOR) proteins represents a prognostic tool in gastric carcinoids, a standardised AgNOR analysis was performed on 24 samples collected from the pathology archives of the Universities of Messina and Parma; the samples were taken at surgery from 11 males and 13 females (mean age 55 yrs, age range 28-77 yrs); 13 cases were defined as Type I, 1 case as Type II and 10 cases as Type III; 16 cases showed a diameter <1 cm, 8 >1 cm. Only 6 tumours were deeply invasive, breaking through the muscularis propria or the subserosa. The proliferative status of carcinoids performed by Ki67 protein antibodies was available in 20/24 cases. The quantification of AgNORs was performed according to the guidelines of the Committee on AgNOR Quantification and the mean area (microm2) of AgNORs per nucleus (NORA) was determined by means of image analyser and specific software programs. The relationship between NORA values and Ki67 data was investigated by Spearman correlation test. The mean NORA value of all 24 gastric carcinoids was 1.279 microm2 (SD 0.404); values ranged from 0.734 to 2.142 microm2. A significantly higher (p < 0.001) mean NORA value (1.736 microm2; SD 0.283) was found in tumours larger than 1 cm, in comparison to the smaller neoplasms (1.051 microm2; SD 0.214); moreover, cases showing deep wall invasion exhibited a mean NORA value of 1.765 microm2 (SD 0.276), significantly higher (p < 0.001) than those with superficial growth (1.118 microm2; SD 0.296). Finally, a similar highly significant difference was seen between type III carcinoids (1.615 microm2; SD 0.375) and type I-II (1.040 microm2; SD 0.208). A linear relationship between Ki67 and corresponding NORA values was obtained by the Spearman correlation test (p = 0.001). No other significant correlations were found between mean NORA values and other clinico-pathological parameters. The AgNOR method seems to be an additional tool potentially able to predict the prognosis of this kind of endocrine tumour, facilitating the identification of fast-growing tumours and being able to directly correlate with the size, deep invasion of gastric wall and tumour type, generally considered as the best prognostic indicators.

Platelet-rich plasma treatment and hemostasis in patients with hemorrhagic risk.

AIM: Our research aimed to evaluate the risk of haemorrhage following oral surgical operations, in patients who were undergoing an anticoagulant therapy, and to test the usefulness of the autologous platelet gel in order to control haemostasis. METHODS: A total of 208 patients (84 males/124 females) undergoing an anticoagulant therapy and submitted to oral surgery, were divided at random into 4 groups (A, B, C, D) consisting of 52 patients each, using as criterion of differentiation the kind of treatment we adopted in order to get haemostasis. The patients belonging to the first 3 groups (A, B, C), underwent a surgical operation without discontinuing the dicumarol therapy. In order to get haemostasis, we used: platelet-rich plasma (PRP) and suture, in group A; PRP, haemostatic sponges and suture, in group B; haemostatic sponges, suture and compression by means of gauzes soaked in tranexamic acid in group C. Group D, instead, consisted of patients who underwent a surgical operation, before which the dicumarol therapy had been suspended and replaced by heparincalcium. RESULTS: Patients belonging to the groups A and B showed a very good haemostasis like the patients of group D (control group). As the coumarin therapy didn't need to be discontinued some days before the surgical operation, so the days of hospital stay were reduced and there wasn't the risk of thromboembolism. As to group C (19 males), 6 patients (i.e. 11.5%) showed a good haemostasis, both at once and in the long term, so that they could be discharged on day 2 after surgery. CONCLUSIONS: The results obtained during our research, highly encourage using PRP regularly when carrying out surgical treatments on patients who are undergoing a coumarin therapy.

Optic disc drusen in tilted disc.

PURPOSE: To investigate if a congenital anomaly of the head of the optic nerve like such as tilted disc can be a risk factor for the development of optic disc drusen. METHODS: The study was performed retrospectively on the files of 47 patients with optic disc drusen. The diagnosis was confirmed by fluorescein angiography and B-scan ultrasonography. The authors examined the fundus photographs and the fluorescein angiographies of these patients looking for the presence of tilted discs. RESULTS: Two of the 47 patients with optic nerve drusen had tilted discs as well, about twice the expected rate. Both cases presented a parapapillary hemorrhage. CONCLUSIONS: The concomitant presence of tilted disc and optic disc drusen can have a cause-effect relationship. The axonal crowding in a scleral canal of reduced size, as seen in tilted disc, can compress the nerve fibers against the stiff lamina cribrosa, producing a chronic optic neuropathy leading to drusen.

Immunolocalization of lactoferrin in surgically resected pigmented skin lesions.

Lactoferrin (Lf) expression was determined immunohistochemically in 57 formalin-fixed paraffin-embedded bioptic samples obtained from an equal number of patients treated by surgery to remove pigmented skin lesions (nevi = 23; melanoma = 12; vulgaris and seborrhoeic warts = 12; basal cell carcinoma = 10); in addition, 10 specimens of normal skin were studied as control. On 3 mm thick sections, depigmentation and antigen retrieval procedures were performed. The Lf immunoreactivity was revealed by a rabbit anti-human Lf. Quantification of Lf immunoreactivity was performed using an intensity-distribution (ID) score. Melanocytic cells, regardless of their benign or malignant nature, were consistently stained, with no significant differences in the Lf ID-score between melanomas or nevi. A different intensity of Lf immunoreactivity was encountered in superficial portions of warts, exclusively inside squamous epithelial cells arranged in sheets or whorls of keratin. On the contrary, basal cell carcinomas were always unstained, while a slight Lf positivity was found in focal keratinized areas present in two tumours showing baso-squamous differentiation. The Lf immunoreactivity was localized in the cytoplasm and only occasionally in the nucleus. The biological meaning of Lf in these cases of human skin specimens remains unexplained, although it cannot be ruled out that Lf might be involved in the defense system against tumours, or alternatively, may be used by cells requiring iron availability for their turnover. Moreover, the immunohistochemical expression of Lf in melanocytic lesions might be also related to a Lf-melanin interaction. Finally, the involvement of Lf in skin squamous non-neoplastic elements could be related to its role as one of the molecules modulating an unspecific inflammatory or anti-oxidant response.