Pathologica 4-07.pdf - Pacini Editore

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Results. A general up-regulation of HIF-1α and its target genes
was observed in cancer compared with normal samples,
with mRNA expression increases by 2- to 1500-folds. High
levels of HIF-1α were significantly associated with poor histological
grade (p < 0.05) and histological type of PDECs (p
< 0.001). A two-way unsupervised hierarchical clustering applied
to the full expression data stratified all samples in two
main branches: cluster I including “normal-like” cancer samples
and cluster II separating tumor samples with significantly
higher expression levels of all genes examined. This second
group comprised 16 out of 18 PDECs and the univariate
analysis showed a significant decrease of overall survival
for patients of cluster II compared with patients of cluster I
(p < 0.04). The univariate analysis showed that poor overall
survival was significantly correlated with: poor histological
grade (p < 0.002), histological type of PDECs (p < 0.001),
advanced tumor stage (p < 0.001), presence of lymph node
metastases (p = 0.0017), and high expression levels of TGFα
(p < 0.001) and NIX (p < 0.01). The multivariate analysis
showed that advanced stage, presence of lymph node metastases
and high levels of TGFα had an independent effect on
survival (p < 0.006; p < 0.01; p < 0.0006). Gene expression
data were used to calculate a predictive score of overall survival
that stratified the patients in a low and a high risk group
(p < 0.0006).
Conclusions. These findings suggest an up-regulation of the
HIF-1 transcriptional pathway in colorectal carcinomas and
confirm in vivo its association with tumor growth and aggressiveness.
A quantitative real time PCR assay can be used
as a sensitive diagnostic technology to measure mRNA from
archival tissue blocks.
Analisi dell’espressione e dello stato genico di
EGFR nel carcinoma colorettale: confronto
S. Crippa, V. Martin, A. Camponovo, M. Ghisletta, S.
Banfi, L. Lunghi-Etienne, L. Mazzucchelli, M. Frattini
Istituto Cantonale di Patologia, Locarno, Svizzera
Introduzione. Cetuximab è un nuovo farmaco nel trattamento
del carcinoma colorettale metastatico (mCRC). I criteri per
la somministrazione del farmaco includono l’immunoreattività
per EGFR, bersaglio molecolare di cetuximab, nel cancro
primitivo. Tuttavia, il cancro primitivo potrebbe mostrare
un profilo molecolare distinto da quello della rispettiva
metastasi. Scopo del presente lavoro è confrontare il grado di
espressione e lo stato genico di EGFR tra i cancri primitivi e
le rispettive metastasi.
Metodi. Abbiamo analizzato l’espressione proteica tramite il
kit PharmDx (Dako) e lo stato genico di EGFR tramite FISH
utilizzando le sonde LSI EGFR/CEP7 (Vysis) in 32 cancri
primitivi consecutivi e nelle rispettive metastasi (sincrone o
metacrone) di pazienti affetti da mCRC, operati dal 2004 al
2006. Un campione è definito amplificato per EGFR quando
l’amplificazione genica è stata osservata in almeno il 10%
delle cellule. La marcata polisomia è definita quando almeno
3 copie del cromosoma 7 sono osservate in più del 50% delle
cellule. Per ogni campione sono state valutate almeno 100
cellule.
Risultati. A livello immunoistochimico abbiamo osservato
immunoreattività per EGFR in 31 casi (97%). L’espressione
della proteina non cambia confrontando il cancro primitivo
con la rispettiva metastasi. All’indagine FISH effettuata sui
cancri primitivi abbiamo osservato disomia in 11 casi (34%),
POSTERS
marcata polisomia in 13 casi (41%), amplificazione genica in
7 casi (22%) e perdita del cromosoma 7 in 1 caso (3%). Nel
confronto con le rispettive metastasi, 17 casi hanno mostrato
lo stesso pattern, mentre differenze sono state osservate in 15
pazienti. Di questi, 5 casi con polisomia o amplificazione nel
cancro primitivo hanno mostrato disomia o polisomia nelle
metastasi, probabilmente a causa della scarsa rappresentatività
della biopsia; 10 casi con disomia del cromosoma 7 nel
cancro hanno mostrato polisomia o amplificazione di EGFR
nelle metastasi, indice di progressiva deregolazione genica.
Non c’è alcuna correlazione tra stato genico ed espressione
proteica di EGFR.
Conclusioni. I nostri dati indicano che l’indagine FISH limitata
al cancro primitivo può sottostimare il numero di pazienti
potenzialmente rispondenti al trattamento con cetuximab;
pertanto è opportuno esaminare anche il campione metastatico
nei pazienti il cui cancro primitivo mostra disomia
per il cromosoma 7.
Il-6 dependent clusterin-Ku-Bax interactions:
apoptosis inhibition and tumor progression.
New in situ and serological marker
S. Pucci, P. Mazzarelli, F. Sesti, E. Bonanno, L.G. Spagnoli
Department of Biopathology, University of Rome “Tor Vergata”,
Italy
Introduction. Several experimental data have shown a
strong correlation between the presence of the different isoforms
of clusterin and tumoral progression. The disappearance
of the proapoptotic form and the overexpression of the
cytoplasmic isoform marks the transition from normal cell to
neoplastic phenotype. Pro-inflammatory cytokines such as
TGFβ and IL-6 influence the transcription of this protein.
TGFβ influences directly clusterin promoter inducing the activation
of the transcription factor AP1. The action of the IL-
6 on the clusterin gene transcript has not been clarified at
molecular level yet. Several experimental evidences underline
an increased production of IL-6 and TGFβ in tumor progression.
It has been observed that the levels of circulating
IL-6 increases in relationship to tumoral mass.
Methods and results. We have focused our attention on defined
pathways that underlie the promotion, initiation and
progression of colon cancer. In particular we examined the
relationship among IL6, clusterin isoforms expression pattern
shift, Ku and Bax interactions in human colon tumorigenesis.
Besides the acquisition of aggressiveness in colon carcinoma
we observed that the overexpression of the secreted
form (sCLU) and disappearance of the pro apoptotic clusterin
isoform, strongly correlates to the inhibition of apoptosis and
the loss of DNA repair activity of the complex Ku70/80.
Moreover we observed an increase in the level of this protein
in the serum and in stools of colon cancer patients as compared
to the control suggesting a strong realease of sclusterin
in the cripta lumen. Preliminary results obtained by ELISA
confirmed that patients affected by colon cancer have a
strong increase of clusterin in blood and in stools and this
level correlated with the IL-6 level suggesting a possible twin
set of new non invasive diagnostic markers.
Conclusions. Hence, in colon cancer biopsies we found the
loss of Ku80 and Ku70 protein translocated from the nucleus
to the cytoplasm where it sterically inhibits cell death induction.
These interactions in colon tumorigenesis are partially