Alberto Righi

p63 expression as a new prognostic marker in merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumor, mostly affecting elderly individuals. The histogenesis of this rare tumor as well as its prognostic criteria are a matter of dispute.

Poorly differentiated carcinoma of the thyroid: validation of the Turin proposal and analysis of IMP3 expression.

The Turin Proposal algorithm defines poorly differentiated carcinoma on the basis of the presence of solid/trabecular/insular growth pattern, absence of conventional nuclear features of papillary carcinoma, and the presence of at least one of the following features: convoluted nuclei, mitotic activity ≥3/10 HPF, or tumor necrosis. IMP3 appears to have diagnostic and prognostic value in many solid tumors, including thyroid carcinomas. We examined a series of follicular-cell carcinomas with prominent solid patterns diagnosed at Mayo Clinic (56 cases) (Rochester, MN, USA) and at the University of Turin (96 cases) (Northern Italy) to validate the Turin consensus criteria defining poorly differentiated carcinoma of the thyroid and to evaluate the prevalence and prognostic behavior of this tumor. On this series, we analyzed the expression of conventional markers by immunohistochemistry and we investigated the expression of IMP3 by both immunohistochemistry and qRT-PCR. The prevalence of poorly differentiated carcinoma among the USA cases was 1.8% (56/3128) and that in the cases of Northern Italy was 6.7% (96/1442). Tumor characteristics were similar in the cases from the USA and from Italy except for extensive vascular invasion and a prevalent insular growth pattern (lower the former, higher the latter in the Italian series). In univariate analysis, the risk of death was higher for age ≥45, tumors ≥4 cm, and IMP3 positivity. Multivariate analysis showed that the risk of death from poorly differentiated carcinoma was higher for age ≥45. The Turin consensus criteria can reliably select poorly differentiated carcinomas. Tumors from the USA and from Italy showed similar overall survival, although the prevalence of poorly differentiated carcinoma was higher in Northern Italy. Expression of IMP3 appears to be an adverse prognostic factor for poorly differentiated thyroid carcinoma.

MicroRNA expression in ileal carcinoid tumors: downregulation of microRNA-133a with tumor progression

MicroRNAs (miRNAs) are involved in cell proliferation, differentiation, and apoptosis and can function as tumor suppressor genes or oncogenes. The role of miRNAs in neuroendocrine tumors such as ileal carcinoids is largely unknown. We examined the differential expression of 95 miRNAs by RT–PCR using the QuantiMir System in eight matching primary and metastatic carcinoid tumors from the ileum. All miRNAs chosen for the QuantiMir System array were based on their potential functions related to cancer biology, cell development, and apoptosis. The expression of miRNAs for the samples was normalized to miRNA-197, and the matching primary and metastatic tumors were compared. There was downregulation of miRNA-133a, -145, -146, -222, and -10b in all samples between the primary and matching metastatic tumors and upregulation of miRNA-183, -488, and -19a+b in six of eight metastatic carcinoids compared to the primary tumors. miRNA-133a was further analyzed by TaqMan real-time RT–PCR and northern hybridization using six additional matching primary and metastatic samples, which supported the PCR array findings. There were significant differences in miRNA-133a expression with downregulation in the metastasis compared to the primary in the eight original cases (P<0.009) and in the six additional cases used for validation (P<0.014). Laser capture microdissection and real-time RT–PCR analysis using normal ileum found miRNA-133a expression in normal enterochromaffin cells. In situ hybridization in normal ileum showed that some of the mucosal endocrine cells expressed miRNA-133a. Both primary and metastatic ileal carcinoid tumors expressed miRNA-133a by in situ hybridization. These results provide information about novel marker miRNAs that may be used as biomarkers and/or therapeutic targets in intestinal carcinoid tumors.

Mammary and vaginal myofibroblastomas are genetically related lesions: fluorescence in situ hybridization analysis shows deletion of 13q14 region

Partial monosomy 13q, a chromosomal alteration originally reported in spindle cell lipoma, has also been documented in a few cases of mammary myofibroblastoma. Subsequently, a monoallelic loss of RB1 and FOXO1, located on 13q14, was identified in some cases of cellular angiofibroma, a benign stromal tumor of the lower female genital tract. This cytogenetic finding and the overlapping morphologic and immunohistochemical features shared by spindle cell lipoma, mammary myofibroblastoma, and cellular angiofibroma strongly suggest a histogenetic link among these tumors. Recently, we have emphasized morphologic and immunohistochemical similarities between mammary and vulvovaginal myofibroblastoma. The aim of the present study was to asses if these 2 tumors share the same chromosomal alteration. We studied the chromosome 13q14 region by fluorescence in situ hybridization analysis in a series of mammary and vaginal myofibroblastomas, with a readable signal in 7 of 13 mammary myofibroblastomas and 5 of 7 cases of vaginal myofibroblastomas. Despite histologic variation, most of the mammary (5/7) and vaginal (3/5) myofibroblastomas showed monoallelic deletion of FOXO1 in more than 22% of the cell populations. Our findings confirm that mammary myofibroblastoma is a tumor that exhibits chromosome abnormalities associated with the loss of the 13q14 region. In addition, we show for the first time that myofibroblastoma of the lower female genital tract also exhibits the same chromosomal abnormality, supporting the hypothesis that both tumors are in the spectrum of a single entity, likely arising from a common precursor cell.

Expression of p63 is the sole independent marker of aggressiveness in localised (stage I–II) Merkel cell carcinomas

Merkel cell carcinoma of the skin is a malignant neuroendocrine tumour, whose prognostic criteria are a matter of dispute. Specifically, no predictor is presently available in stage I–II tumours. We collected clinical and follow-up data from 70 Merkel cell carcinomas of the skin. The same cases were studied for p63 expression by immunohistochemistry, by reverse-transcription PCR (RT-PCR) and TP63 gene status by FISH and for presence of Merkel cell polyomavirus by PCR. Stage emerged as a significant prognostic parameter (P=0.008). p63 expression, detected in 61% (43/70) of cases by immunohistochemistry, was associated with both decreased overall survival (P<0.0001) and disease-free survival (P<0.0001). Variable expression patterns of the different p63 isoforms were found only in cases immunoreactive for p63. In these latter lesions, at least one of the N-terminal p63 isoforms was detected and TAp63α was the most frequently expressed isoform. TP63 gene amplification was observed by FISH in only one case. Presence of Merkel cell polyomavirus DNA sequences was detected in 86% (60/70) of Merkel cell carcinomas and did not emerge as a significant prognostic parameter. Merkel cell carcinoma cases at low stage (stage I-II) represented over half (40/70 cases, 57%) of cases, and the clinical course was uneventful in 25 of 40 cases while 15 cases died of tumour (10/40 cases) within 34 months or were alive with disease (5/40 cases) within 20 months. Interestingly, a very strict correlation was found between evolution and p63 expression (P<0.0001). The present data indicate that p63 expression is associated with a worse prognosis in patients with Merkel cell carcinoma, and in localised tumours it represents the single independent predictor of clinical evolution.

PEComa: Another Member of the MiT Tumor Family?

We report 2 cases of PEComa, one occurring in the colon of an 11-year-old boy and the other in the bone (fibula) of a 92-year-old woman. Both tumors consisted of nests of large epithelioid cells surrounded by a fibrovascular stroma. The nuclei were large and vesicular, with prominent centrally located nucleoli. The cytoplasm was eosinophilic, with a fine to coarse granularity. Mitoses and individual cell necrosis were infrequent. Immunohistochemically, both tumors showed strong cytoplasmic expression of HMB-45 and intense nuclear positivity for TFE3. To our knowledge, nuclear positivity for TFE3 has been previously reported in only 5 cases of PEComa. Reactivity to this marker suggests that PEComa should be added to the growing list of human tumors of the so-called MiT family gene.

A classification tree approach for pituitary adenomas

It is difficult to evaluate the recurrence and progression potential of pituitary adenomas at presentation. The World Health Organization classification of endocrine tumors suggests that invasion of the surrounding structures, size at presentation, an elevated mitotic index, a Ki-67 labeling index higher than 3%, and extensive p53 expression are indicators of aggressive behavior. Nevertheless, Ki-67 and p53 labeling index evaluation is subject to interobserver variability, and their cutoff values are controversial. In the present study, the prognostic value of Ki-67 and p53 protein labeling indices and their correlation with clinical and radiologic parameters were evaluated using digital image analysis in a series of 166 pituitary adenomas in patients having undergone a follow-up of at least 6 years to evaluate the impact on the recurrence and progression potential of pituitary adenomas. The data were analyzed using the receiver operating characteristic curve and classification and regression tree analysis. The results showed that, in the unstratified data set, the commonly used threshold of the Ki-67 index of 3% has a high specificity (89.5%) but a low sensitivity (53.8%). Unsatisfactory performance results were obtained by performing receiver operating characteristic curve analysis on the p53 labeling index. On the contrary, the classification and regression tree analysis-derived tree demonstrated that each pituitary adenoma subtype has specific prognostic factors. Specifically, the Ki-67 labeling index is a useful prognostic factor in nonfunctioning, adrenocorticotropin, and prolactin adenomas, but with different thresholds. In conclusion, our study emphasizes that the term pituitary adenomas includes different types of tumors, each one having specific prognostic factors.

Galectin-3 expression in pituitary adenomas as a marker of aggressive behavior

The purpose of this retrospective study was to investigate the role of galectin-3 (LGALS3) expression in predicting the recurrence and the progression potential of prolactin (PRL) and adrenocorticotropic hormone (ACTH)-producing pituitary adenomas and its correlation with the RUNX1 and RUNX2 transcription factors involved in the regulation mechanism of LGALS3 expression. Clinical, neuroradiologic, and follow-up data from 92 pituitary adenomas, including 59 PRL cell adenomas and 33 ACTH-functioning pituitary adenomas, were collected. The LGALS3 expression was analyzed by both immunohistochemistry and quantitative real time-polymerase chain reaction, whereas RUNX1 and RUNX2 were analyzed by quantitative real time-polymerase chain reaction only. The data obtained indicated that invasive growth with suprasellar extension, Ki-67 labeling index, and LGALS3 immunohistochemical and/or LGALS3 messenger RNA levels are the most important histologic features for assessing a high risk of progression or recurrence of PRL- and ACTH-functioning pituitary adenomas. Multivariate Cox regression analysis assessed LGALS3 immunohistochemical positivity in at least 30% of neoplastic cells and/or LGALS3 messenger RNA positivity (P < .001) as strong predictive factors of recurrence/tumor progression followed by a Ki-67 labeling index greater than 3% (P = .019) in the 81 cases in which follow-up data were available. In addition, a significant correlation between LGALS3 and RUNX1 expression levels (P = .0435) was found. This retrospective immunohistochemical and molecular study demonstrated that LGALS3 expression appeared to be a predictive factor of the aggressive behavior of PRL- and ACTH-functioning pituitary adenomas, and its expression was correlated with RUNX1 expression levels.

Papillary thyroid carcinoma with hobnail features: histopathologic criteria to predict aggressive behavior.

Recent reports indicate that papillary thyroid carcinoma with hobnail features, also designated as micropapillary variant of papillary thyroid carcinoma, is a rare but very aggressive variant of papillary thyroid carcinoma. We examined the histopathologic and immunohistochemical features of 24 cases of papillary thyroid carcinoma with hobnail/micropapillary component to determine the prognostic significance of the amount of hobnail/micropapillary features in these tumors. The patients included 18 women and 6 men. Ages ranged from 28 to 78 years (mean, 57 years). Tumor size ranged from 1 to 5.8 cm (mean, 3 cm). The average follow-up time was 106 months (range, 4-274 months). Twelve cases (50%) of papillary thyroid carcinoma showed more than 30% hobnail/micropapillary features, and all but 3 cases were associated with an aggressive behavior. During the follow-up, 6 of these patients died of disease after a mean of 44.8 months, and 3 patients remained alive with extensive disease after a mean follow-up of 32.3 months. Metastases to lymph nodes or distant organs showed a hobnail pattern of growth similar to the primary tumor. The remaining 3 patients with prominent hobnail/micropapillary features were alive with no evidence of disease after a mean follow-up of 125.3 months. The other 12 papillary thyroid carcinoma cases (50%) showed less than 30% hobnail/micropapillary features. Nine of these patients were alive without disease after a mean of 162 months, and 1 patient died of sepsis, which was not related to thyroid tumor after 155 months. Two patients in this group died of disease after 21 and 163 months, respectively. These findings confirm earlier observations that papillary thyroid carcinoma with hobnail/micropapillary features is an aggressive variant of papillary thyroid carcinoma. Tumors with more than 30% hobnail/micropapillary features were often very aggressive, although 2 patients with tumors with 10% hobnail/micropapillary features also had poor outcomes.

E-cadherin loss and ΔNp73L expression in oral squamous cell carcinomas showing aggressive behavior

This article sought to investigate the existence of parameters useful for predicting lymph node metastases in cases of surgically resected oral squamous cell carcinomas (OSCCs).