Immuno Thread

[LADoc00]

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Okay let me start this off.

Metastatic adenocarcinomas of unknown primary origin. Is anyone out there in academics got a good line on a pancreatic marker that is highly specific??

 

[b&ierstiefel]

Okay let me start this off.

Metastatic adenocarcinomas of unknown primary origin. Is anyone out there in academics got a good line on a pancreatic marker that is highly specific??

Looking for the loss of DPC4/Smad4 is helpful but not always. If expression of Smad4 is lost, great! You got a pancreatic primary. However, there is a significant subset of pancreatic tumors that do not lose Smad4 expression.

I'm not aware of a marker that, when it's positive, is specific for pancreatic cancer.

 

[LADoc00]

Thanks for a reply, yes SMAD4 genetic inactivation has been described in pancreatic adeno's but I was unaware that anyone was using IHC loss as a marker.

 

[b&ierstiefel]

Thanks for a reply, yes SMAD4 genetic inactivation has been described in pancreatic adeno's but I was unaware that anyone was using IHC loss as a marker.

Yeah, we use it quite a bit and find it very helpful in selected cases.

 

[mcfaddens]

Someone here is working on using KOC, and it worked very well in FNA specs not too sure about histo though I can look into it if your interested

 

[yaah]

Here they just use CKs and occasionally CDX2 to rule out colon. We had a case this week of a colon mass in a pt with pancreatic cancer, could have been either colon or pancreas although it kind of looked like pancreas. CDX2 was neg in the tumor but pos in the surface colon, CK7 and 20 both positive in the tumor. CK20 was neg in the surface. Of course, that can be unreliable because CDX2 can be positive in some pancreatic CA, and 7 and 20 are not that reliable to distinguish it.

 

[RyMcQ]

Here they just use CKs and occasionally CDX2 to rule out colon. We had a case this week of a colon mass in a pt with pancreatic cancer, could have been either colon or pancreas although it kind of looked like pancreas. CDX2 was neg in the tumor but pos in the surface colon, CK7 and 20 both positive in the tumor. CK20 was neg in the surface. Of course, that can be unreliable because CDX2 can be positive in some pancreatic CA, and 7 and 20 are not that reliable to distinguish it.

What is the deal with CDX2? It seems to be positive when CD20 is positive. (At least, that's what the presenter at the CAP companion meeting seemed to be saying in March.) Pancreatic cases that are positive for CDX2 tend to be positive for CD20. Is the extra marker actually that helpful?

 

[LADoc00]

What is the deal with CDX2? It seems to be positive when CD20 is positive. (At least, that's what the presenter at the CAP companion meeting seemed to be saying in March.) Pancreatic cases that are positive for CDX2 tend to be positive for CD20. Is the extra marker actually that helpful?

CDX2 is supposed to be a GI specific nuclear transcription factor ala TTF-1.

I wish I could find some of these tumor associated TFs, patent them and market the ab...$$

 

[l&usibari]

Someone here is working on using KOC, and it worked very well in FNA specs not too sure about histo though I can look into it if your interested

KOC is not at all specific for pancreas.

 

[l&usibari]

CDX2 is not specific for GI! Check immunoquery, CDX2 stains tissues from a variety of organs. CDX2 is mis-used, IMO.

 

[djmd]

They say the only specific antibodies are the ones that have not been studied enough...

 

[b&ierstiefel]

They say the only specific antibodies are the ones that have not been studied enough...

You know, I was thinking the same thing. The more studies that are done, I'm worried that the picture will only become more clouded.

 

[deschutes]

Ipox.org (http://www.ipox.org/) came to my attention recently - I don't think it's been mentioned before on these forums.

Seems you can put in 3 markers and it'll spit out diagnoses in order of likelihood.

 

[yaah]

Well, I asked a couple of GI path people here and like every above said, no, there is no pancreas specific marker. Sorry.