Sevan: honestly: you 'CAN' do that all.

The question is:

> Does it benefit ? < the research task you are struggling with.....

While surgeons not only in your country are prone to "make it simple" and place tissue specimens generally or with preference (according to SOP's or requirements of Histology Labs) into fixative (usually in the end to be processed and analyzed in a Pathology Lab), you might have other intentions or needs as your analyzing methods demands.

I do not know whether quick immersion and imbibition of tissue specimens into correctly made up 4% BUFFERED*) formaldehyde after ONLY 3-5 hrs initial fixation (guessing: at elevated?/normal? RT) is of NO value for DNA or RNA analysis [as it decreases DNA and RNA-yield by 10-35%, cf. #) and other sources].

Usually good fixation is necessary for the task of the following diagnostic histological examination (preservation of morphology and stainability) and NBF or similar (form-)aldehyde solutions most often turned out to be superior to other "fixatives" (e.g. cf.:

Free article: MOELANS et al, Formaldehyde Substitute Fixatives: Analysis of Macroscopy, Morphologic Analysis, and Immunohistochemical Analysis

in:

American Journal of Clinical Pathology, Volume 136, Issue 4, October 2011, Pages 548–556, https://doi.org/10.1309/AJCPHH1B0COCBGOM or: https://academic.oup.com/ajcp/article/136/4/548/1760595),

so if you need other preferences to be settled, you perhaps need to divide surgical tissue for

i) the main purpose (e.g. diagnostic histology) and - on the other hand -

ii) your preferred method/analysis technique (where - depending on the case - it might be difficult to discern or to decide, how much should be processed for histology and how much / which part should be saved for additional analyses).

I would have more concerns when using '1x' PBS (most of commercially available 'PBS' = phosphate buffered saline, designated '1x' are hypo-osmolar...= only 0.01 M (if I remember correctly....but that will depend also on the composition of the ionic components used in the solution)

Concerning your special questions:

[NB: you always "CAN" ....see above =(:-)) ]

• Can I take this sample and put in 1xPBS until I will go to laboratory ?

Depending on the time that will elapse when walking from the surgery theatre to your lab/working place I propose to use only PBS- (or 0.9% physiol. NaCl- ) soaked or better: only moistened! gauze (pads) swabs, which for safe transportation - CAVE: drying out! - are placed into a "moisty chamber"-container). That, IMHO would be the most elegant and less costeffective action...

• Can I take this sample for 1x PBS and then put it in liquid nitrogen until I use?

Not knowing if you meant "from" instead of "for" 1x PBS,

I think that NATURALLY it is the best option to FREEZE the specimen (cave: volume/size should not exceed a certain limit!) by plunging into LN2

• Can I put formalin fixed cancer tissue in liquid nitrogen for preservation?

This is - as to my minor knowledge - an approach often used in preserving tissue not only for further / LATER histological but also necessary molecular-biological and biogenetical analytical techniques.

Of course - you wouldn't freeze your tissue containing too much free and unbound (form-)aldehyde molecules in your fixed tissue....so washings in appropriate buffer solution (be it either phosphate buffered or zwitterionic = e.g., HERPES or PIPES-buffered ) are recommended and necessary before plunge-freezing in LN2 (NB: tissue/specimen parts after lat washing should be thorougly but nevertheless carefully wicked in/with filter or kitchen (paper) towels to get rid of excess isolating hydrous liquid.

It certainly would be of help if you could inform more in detail about the research task you have to perform.

And - last but not least: as usual, you shouldn't bother 'the surgeons' who should help you in collecting the valuable material you (have to) examine....(:-)).

*) 'BUFFERED' means: either NBF#) = neutralized buffered FORMALIN**) or Formaldehyde [NB: **) "trade name of MERCK": 'Formalin(R) or (TM)' ) as a min. 38% hydrous solution for Histology]

**) cf.: Lillie RD: Histopathologic Technic and Practical Histochemistry, New York, NY, McGraw-Hill, 1965

#) cf. e.g. : https://www.thermofisher.com.au/Uploads/file/Common/IFU/Neutral_Buffered_Formalin_IFU.pdf

Best wishes, good luck

Addendum: just because I stumbled over this one on search in my files:

I honestly would propose/invite you to read (not only, try full text search (find: SEARCH icon/field in rectangle] in RG-repository/archives...publications and Q/A=questions and answers):

https://www.researchgate.net/post/What_is_the_difference_between_fresh_frozen_tissues_and_tissues_frozen_in_tissue_freezing_medium

Dear Wolfgang H. Muss

Thanks for your information.

You're welcome, dear Sevan.