Tumor prognosis question

[Phloston]

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Why is elevated lactate dehydrogenase considered a poor prognostic factor with regard to tumours?

And why is poor response to radiation therapy not considered a poor prognosis factor?

GT has stated the above two without explanation in one of their practice questions.

Cheers,

 

[HelpPleaseMD]

lactate dehydrogenase is used as a marker for the aggressiveness of the tumor.
I am guessing that poor response to radiation therapy is not considered a poor prognosis factor cause it could mean that the tumor is very slow growing like maybe a follicular lymphoma

 

[Phloston]

lactate dehydrogenase is used as a marker for the aggressiveness of the tumor.
I am guessing that poor response to radiation therapy is not considered a poor prognosis factor cause it could mean that the tumor is very slow growing like maybe a follicular lymphoma

I had thought lymphomas were among the fastest growing...

Robbin's Review of Path had stressed that they have very high growth fractions.

 

[HelpPleaseMD]

http://www.nhlcyberfamily.org/types/follicular.htm

 

[Phloston]

The article says "Follicular lymphoma is a slow growing type of NHL...," not that follicular lymphoma itself is a slow-growing tumour.

Lymphomas have high growth-fraction, but follicular lymphoma is a slower growing one of the NHLs.

Anyway, I hadn't meant to delve into those technicalities. Thanks for your post.

I would assume upregulation of LDH means increased ability for cellular proliferation in hypoxic/under-vascularized environments.

 

[StIGMA]

The article says "Follicular lymphoma is a slow growing type of NHL...," not that follicular lymphoma itself is a slow-growing tumour.

You misunderstood this statement. If A is slow and A is a type of B... A is still slow. NHL is a category, of which FL is a part of. And FL is slow growing. From my understanding, resistance to radiation can mean a good or bad prognosis depending on the cancer. When it is a good prognosis, it is because the tumor is slow growing, eg: not too invasive/genetically unstable.


In regard to LDH, more LDH implies more tumor. More tumor = bad.

 

[Phloston]

You misunderstood this statement. If A is slow and A is a type of B... A is still slow. NHL is a category, of which FL is a part of. And FL is slow growing. From my understanding, resistance to radiation can mean a good or bad prognosis depending on the cancer. When it is a good prognosis, it is because the tumor is slow growing, eg: not too invasive/genetically unstable.


In regard to LDH, more LDH implies more tumor. More tumor = bad.

Stigma, there was nothing misunderstood, but I appreciate the lettered analogy. What's written in the article is clear.

With a larger tumour, we'd expect increased production of anything, so to say increased size = increased LDH is very non-specific. The increased LDH, as I've reasoned through it, means increased anaerobic glycolytic capacity, which would facilitate growth when angiogenesis is still preliminary.

 

[StIGMA]

The increased LDH, as I've reasoned through it, means increased anaerobic glycolytic capacity, which would facilitate growth when angiogenesis is still preliminary.

The LDH measured in these tests is from lysed tumor cells (LDH released into the bloodstream), and is a general "marker of cell turnover" as written in the article below. Any number of proteins could be used for this 'cell turnover' measurement, but LDH is the one used. Large/Invasive tumors often have dead/necrotic zones which will release LDH. Moreover, tumor cell turnover is relatively high (many cells dying), and larger tumors will have more cell turnover (more LDH release). Note that these authors are using LDH as a marker for metastasis, not early lesions. I am not sure how well LDH is a marker for early lesions, but I doubt it would be very specific.

http://www.asco.org/ascov2/Meetings/Abstracts?&vmview=abst_detail_view&confID=55&abstractID=32571