Marco Losa

PI3KCA/PTEN deregulation contributes to impaired responses to cetuximab in metastatic colorectal cancer patients

BACKGROUND It has been reported that KRAS mutations (and to a lesser extent KRAS mutations with the BRAF V600E mutation) negatively affect response to anti-epidermal growth factor receptor (EGFR) mAbs in metastatic colorectal cancer (mCRC) patients, while the biological impact of the EGFR pathway represented by PI3K/PTEN/AKT on anti-EGFR treatment is still not clear. PATIENTS AND METHODS We analysed formalin-fixed samples from a cohort of 32 mCRC patients treated with cetuximab by means of EGFR immunohistochemistry, EGFR and PTEN FISH analysis, and KRAS, BRAF, PI3KCA, and PTEN genomic sequencing. RESULTS Ten (31%) of 32 patients showed a partial response to cetuximab and 22 (69%) did not [nonresponder (NR)]. EGFR immunophenotype and FISH-based gene status did not predict an anti-EGFR mAb response, whereas KRAS mutations (24%) and PI3K pathway activation, by means of PI3KCA mutations (13%) or PTEN mutation (10%)/loss (13%), were significantly restricted to, respectively, 41% and 37% of NRs. CONCLUSION These findings suggested that KRAS mutations and PI3KCA/PTEN deregulation significantly correlate with resistance to cetuximab. In line with this, patients carrying KRAS mutations or with activated PI3K profiles can benefit from targeted treatments only by switching off molecules belonging to the downstream signalling of activated EGFR, such as mammalian target of rapamycin.

Results of Transsphenoidal Surgery in a Large Series of Patients with Pituitary Adenoma

OBJECTIVE: To report the efficacy and safety of microsurgical transsphenoidal surgery in a series of previously untreated patients with pituitary adenoma. METHODS: One thousand one hundred forty consecutive patients undergoing transsphenoidal resection of a pituitary adenoma at our department from January 1990 through December 2002 were included in our study. Postoperative results were classified uniformly during the period of the study. Patients were considered in remission of disease when strict hormonal and radiological criteria of cure were met. RESULTS: The most frequent tumor type was clinically nonfunctioning adenoma (NFPA) (33.2%), followed by growth hormone-secreting adenoma (28.1%), adrenocorticotropin-secreting adenoma (23.0%), prolactin-secreting adenoma (13.2%), and last, thyrotropin-secreting adenoma (2.5%). The patient population was 59.7% female and 40.3% male. Mean age was 43.0 ± 0.4 years. There were 788 macroadenomas (69.1%), and in 233 patients (20.4%), the tumor invaded one or both cavernous sinuses. The overall rate of early surgical success was achieved in 504 (66.1%) of the 762 patients with a hormone-active adenoma. Surgical outcome was better in patients with microadenomas than in patients with macroadenomas (78.9% and 55.5%, respectively), whereas tumors invading the cavernous sinus had a poorer outcome (7.4%). In patients with NFPA, no residual adenoma was present in 234 patients (64.8%). Normalization of visual defects occurred in 117 (40.5%) of the 289 patients with visual disturbances and improved in another 148 patients (51.2%). Three patients (0.3%) died as a consequence of surgery. CONCLUSION: Transsphenoidal surgery is an effective and safe treatment for most patients with pituitary adenoma and could be considered the first-choice therapy in all cases except for prolactinomas responsive to dopamine agonists. Other treatment methods, such as radiotherapy, stereotactic radiosurgery, and medical therapy, play an important role in patients not cured by surgery.

Retinoic acid prevents experimental Cushing syndrome

Cushing syndrome is caused by an excess of adrenocorticotropic hormone (ACTH) production by neuroendocrine tumors, which subsequently results in chronic glucocorticoid excess. We found that retinoic acid inhibits the transcriptional activity of AP-1 and the orphan receptors Nur77 and Nurr1 in ACTH-secreting tumor cells. Retinoic acid treatment resulted in reduced pro-opiomelanocortin transcription and ACTH production. ACTH inhibition was also observed in human pituitary ACTH-secreting tumor cells and a small-cell lung cancer cell line, but not in normal cells. This correlated with the expression of the orphan receptor COUP-TFI, which was found in normal corticotrophs but not in pituitary Cushing tumors. COUP-TFI expression in ACTH-secreting tumor cells blocked retinoic acid action. Retinoic acid also inhibited cell proliferation and, after prolonged treatment, increased caspase-3 activity and induced cell death in ACTH-secreting cells. In adrenal cortex cells, retinoic acid inhibited corticosterone production and cell proliferation. The antiproliferative action and the inhibition of ACTH and corticosterone produced by retinoic acid were confirmed in vivo in experimental ACTH-secreting tumors in nude mice. Thus, we conclude that the effects of retinoic acid combine in vivo to reverse the endocrine alterations and symptoms observed in experimental Cushing syndrome.

Early results of surgery in patients with nonfunctioning pituitary adenoma and analysis of the risk of tumor recurrence

OBJECT Nonfunctioning pituitary adenomas (NFPAs) are benign tumors of the pituitary gland that typically cause visual and/or hormonal dysfunction. Surgery is the treatment of choice, but patients remain at risk for tumor recurrence for several years afterwards. The authors evaluate the early results of surgery and the long-term risk of tumor recurrence in patients with NFPAs. METHODS Between 1990 and 2005, 491 previously untreated patients with NFPA underwent surgery at the Università Vita-Salute. Determinations of recurrence or growth of the residual tumor tissue during the follow-up period were based on neuroradiological criteria. RESULTS Residual tumor after surgery was detected in 173 patients (36.4%). Multivariate analysis showed that invasion of the cavernous sinus, maximum tumor diameter, and absence of tumor apoplexy were associated with an unfavorable surgical outcome. At least 2 sets of follow-up neuroimaging studies were obtained in 436 patients (median follow-up 53 months). Tumors recurred in 83 patients (19.0%). When tumor removal appeared complete, younger age at surgery was associated with a risk of tumor recurrence. In patients with incomplete tumor removal, adjunctive postoperative radiotherapy had a marked protective effect against growth of residual tumor. CONCLUSIONS Complete surgical removal of NFPAs can be safely achieved in > 50% of cases. Visual symptoms and, less frequently, pituitary function may improve after surgery. However, tumor can recur in patients after apparently complete surgical removal. In patients with incomplete tumor removal, radiation therapy is the most effective adjuvant therapy for preventing residual tumor growth.

Molecular and cytogenetic subgroups of oropharyngeal squamous Cell carcinoma

Purpose: The aim of this study was to acquire further insights into the pathogenetic pathways of head and neck squamous cell carcinomas (HNSCC) that may be useful for identifying new biomarkers instrumental in developing more specific treatment approaches. Experimental Design: Cell cycle regulators and epidermal growth factor receptor (EGFR) and BRAF genes were analyzed in a series of 90 oropharyngeal SCCs of a cohort of surgically treated patients from a single institution, and the results were matched with the presence of high-risk human papillomavirus (HR-HPV) DNA and the TP53 status. Results: At least four distinct groups of tumors were identified sharing a common histology but displaying different molecular/cytogenetic patterns: (a) 19% were HPV-positive SCCs whose lack of alterations of the investigated genes could explain their particular natural history, which requires less aggressive treatment; (b) 37% were HPV-negative SCCs carrying TP53 mutations, which may be more effectively treated by drugs acting through p53-independent apoptosis; (c) 34% were HPV-negative SCCs carrying wild-type TP53 and loss of 9p21 (p16INK4a and p15INK4b) and/or cyclin D1 overexpression that justify treatment with DNA-damaging drugs followed by cell cycle inhibitors; and (d) 10% were HPV-negative lacking tumor suppressor genes and cell cycle alterations. The second, third, and fourth groups also showed an increased copy number of EGFR and chromosome 7 (43%) that might justify the additional or alternative use of EGFR inhibitors. Conclusions: Our findings suggest that assessing HPV, TP53, 9p21, and EGFR status may be crucial to finding more tailored and beneficial treatments for oropharyngeal SCCs.

Cetuximab in recurrent and/or metastatic salivary gland carcinomas: A phase II study

EGFR overexpression in salivary gland carcinomas provides the rational for the investigation of anti-EGFR treatments in recurrent and/or metastatic salivary gland cancers (RMSGCs). The activity of cetuximab in terms of clinical benefit rate (CBR) defined as the occurrence of objective response (CR or PR) or stable disease (SD) for >or=6months was investigated. From April to December 2005, 30 patients [23 adenoid cystic carcinoma (ACC) and 7 non-ACC] were treated with cetuximab at 400mg/m(2)/week followed by 250mg/m(2)/week until progression, major toxicity or voluntary discontinuation. EGFR expression and gene status were retrospectively analyzed by immunocytochemistry and fluorescence in situ hybridization, respectively. A median of 14 courses of cetuximab (range 5-54) were infused. Skin toxicity was the main adverse event. Cetuximab provides a CBR in 50% (95% CL, 31 to 69%) of cases. None tumor sample showed EGFR gene amplification and an increased EGFR copy number was observed in 12% of samples, all ACC. Skin rash >or=G2, EGFR overexpression and EGFR copy number were not statistically correlated to CB. In RMSGCs further evaluations of EGFR targeting agents are advisable and should take place by appropriate tumor biological selection, differentiating ACC from non-ACC.

Proliferation index of nonfunctioning pituitary adenomas: Correlations with clinical characteristics and long-term follow-up results

OBJECTIVEThe recurrence of nonfunctioning pituitary adenomas (NFPAs) after surgical removal is common. The aim of our study was to investigate and correlate the growth fraction of NFPAs with clinical characteristics and long-term follow-up results. METHODSTumor specimens were obtained from 101 consecutive patients with NFPAs (48 female patients and 53 male patients; mean age, 52.0 ± 1.5 yr). Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immunocytochemical analysis using the monoclonal antibody MIB-1. The Ki-67 antigen labeling index (LI) was determined by counting a total of at least 1000 neoplastic nuclei. RESULTSThe mean Ki-67 LI for the 101 patients was 2.4 ± 0.3% (range, 0–23.0%). Only age at surgery was inversely correlated with the Ki-67 LI; sex, maximal tumor diameter, and invasiveness into the cavernous sinuses did not significantly affect the Ki-67 LI. The mean follow-up period was 39.7 ± 2.1 months. During follow-up monitoring, 23 patients experienced tumor recurrence, after a mean period of 28.6 ± 4.8 months. Invasiveness of the tumor on preoperative magnetic resonance imaging scans was the strongest predictor of late tumor recurrence, followed by previous pituitary surgery, younger age, and lack of postoperative radiotherapy. The Ki-67 LI had no independent prognostic value. CONCLUSIONOur study suggests that the clinical characteristics of patients with NFPAs, except for age at surgery, are not correlated with the Ki-67 LI. Moreover, the Ki-67 LI does not seem to provide independent information to identify patients at high risk for tumor recurrence.

The role of stereotactic radiotherapy in patients with growth hormone-secreting pituitary adenoma

CONTEXT Single-session stereotactic radiotherapy (SR) may be a potential adjuvant treatment in acromegaly. OBJECTIVE We analyzed the safety and efficacy of SR in patients who had previously received maximal surgical debulking at our center. DESIGN The study was a retrospective analysis of hormonal, radiological, and ophthalmologic data collected in a predefined protocol from 1994 through 2006. SETTING The study was performed at a university hospital. PATIENTS Eighty-three acromegalic patients, 52 women and 31 men, with a mean age of 42.6 +/- 1.2 yr, participated in the study. The median follow-up was 69 months (interquartile range 44-107 months). INTERVENTION The patients were treated with SR for residual or recurrent GH-secreting adenoma. MAIN OUTCOME MEASURE Normalization of age- and sex-adjusted IGF-I levels together with a basal GH level below 2.5 microg/liter without concomitant GH-suppressive drugs was the goal of therapy. RESULTS Fifty patients (60.2%) reached the main outcome of the study. The rate of remission was 52.6% at 5 yr [95% confidence interval (CI) 40.6-64.6%]. Another 13 patients (15.7%), who were resistant to somatostatin analogs, were in remission after SR. Multivariate analysis showed that low basal GH and IGF-I levels were associated with a favorable outcome. No serious side effects occurred after SR. The 5-yr cumulative risk of new onset hypogonadism, hypothyroidism, or hypoadrenalism was 3.6% (95% CI 0-8.6%), 3.3% (95% CI 0-7.7%), and 4.9% (95% CI 0-10.4%), respectively. CONCLUSION In a highly selected group of acromegalic patients, SR treatment had good efficacy and safety. This may lead to reconsider the role of SR in the therapeutic algorithm of acromegaly.

Surgical treatment of giant pituitary adenomas: strategies and results in a series of 95 consecutive patients.

OBJECTIVEGiant pituitary adenomas, defined as those measuring at least 4 cm in maximum diameter, are a therapeutic challenge. We report our experience in a large, consecutive series of patients with giant adenomas. METHODSBetween 1990 and 2004, 95 patients with a giant pituitary adenomas underwent surgery at our department. Nonfunctioning pituitary adenoma was the most frequent type (n = 70; 73.7%), whereas hormone-secreting adenomas numbered only 25 (26.3%). The mean age at the time of surgery (±standard error of the mean) was 48.4 ± 1.5 years; there were 66 men (69.5%) and 29 women (20.5%). RESULTSIn total, 111 surgical procedures were performed. Of these, 85 approaches (76.6%) were transsphenoidal and 26 (23.4%) were transcranial. Visual improvement occurred in 59 of the 79 patients with preoperative defect who could be evaluated after surgery (74.7%). Radical tumor excision was obtained in 14 patients (14.7%). Adjuvant medical and radiation therapies led to 74.5% (95% confidence interval, 62.7–86.4%) control of tumor growth at 5 years. This was not different in patients with nonfunctioning pituitary adenomas compared with patients with hormone-secreting tumors. In the subgroup of patients with nonfunctioning pituitary adenomas, radiation therapy had a protective role against tumor growth (P < 0.01). CONCLUSIONMaximal surgical removal of giant adenomas through the transsphenoidal or transcranial approach, or both, aimed to relieve compression of the optic pathway and reduce tumor volume as much as possible, offers the best chances to control the tumor when followed with adjuvant medical and radiation therapies.

Treatment relevant target immunophenotyping of 139 salivary gland carcinomas (SGCs)

Salivary gland carcinomas (SGCs) are rare tumors encompassing a wide spectrum of histologic/biologic entities. Standard non-surgical treatments are ineffective in case of advanced disease. Our aim was to analyze SGCs deregulation gene profiles that could become target for innovative treatment options. Samples from 139 patients with primary, recurrent and/or metastatic SGCs were investigated by immunohistochemistry for protein encoded by tyrosine kinases receptors (TKRs) i.e. c-kit, HER2, EGFR and hormonal receptors, i.e. androgen (AR), estrogen (ER) and progesterone receptors (PgR). In 26 cases, the HER2 immunohistochemical analysis was complemented by fluorescence in-situ hybridization analysis. EGFR was the most expressed TKRs (71%) and it was found across all histotypes. c-Kit expression was mainly restricted to adenoid cystic carcinoma (78%) while HER2 expression, mostly sustained by gene amplification, correlated with salivary duct carcinoma (SDC) in 44% of cases and adenocarcinoma, not otherwise specified (AD, NOS) in 21% of cases. With respect to histogenetic classification, TKRs expression occurred more often in tumors derived from intercalated duct rather than excretory ones with the only exception of HER2. AR was found in 13% of samples, restricted to SDC and AD, NOS and it was co-expressed with HER2 in more than half of the SDC cases. ER and PgR positivity was never detected. This TK-hormonal receptors analysis identify a histotype-specific profiles that could be exploited for better selecting patients for innovative treatment within prospective studies.