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FAQs | Fees | Forms | Contact | Procedures and Tissue Handling


Our purpose is to provide convenient histology services with the highest quality to researchers. We perform all standard histology procedures including grossing, processing, embedding, and sectioning of paraffin embedded samples. We use custom histological procedures, designed to best fit the needs of the research project.

We provide the following services:

  • Processing
  • Paraffin embedding
  • Sectioning
  • Routine H & E
  • Frozen sectioning
  • Cryostat use
  • Sections / Cores for RNA isolation
  • Sections / Cores for DNA isolation
  • Select Special Stains (AFB and MAS)
  • Consultations for tissue preparation
  • Preparation of tissue for LCM/ frozen and paraffin sectioning and staining

We accept the following specimen types:

  • Human tissues
  • Animal tissues
  • Cell lines
  • Xenografts

We offer:

  • Short turnaround times

    NOTICE: Hazardous or pathogenic tissue samples must be indicated.

What we will need to know

Questions we will ask:

  • What solution is the tissue in now?
  • What type of fixative was used, and for how long has the tissue been in fix?
  • Can the tissue be cut down to a size appropriate for processing?
  • Do you want to submit all the tissue or just a representative section?
  • If the tumor is bisected do both pieces NEED to be in ONE cassette?
  • If you are requesting more than one H&E, do you want these to be levels (sections collected at different depths)?
  • If there are multiple tumors of the same treatment group how many do you want processed and how many blocks do you want made?
  • Are your unstained slides going to be used for immuno?
  • Are your unstained slides going to be used for DNA OR RNA extraction?
  • Does your protocol require us to use DEPC water or distilled water in our water baths?
  • If you're planning to do LCM are you aware that our H&E stainer is used to stain cases other than yours and should be considered contaminated? We can hand stain your slides

The following questions pertain to frozen sections:

  • Do you want the sections fixed?
  • What do you want them fixed in?
  • How thick do you want the sections?
  • Are there any special requirements for the tissue such as low light for fluorescence?
  • Do you want to purchase a slide box to store your sections in the freezer or can you supply one to us?
  • Do you want an H&E to go with the unstained sections? An H&E allows you to see the basic morphology of the tissue.
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Please note that these prices are for JHU Cancer Center members. Rates for non-cancer members affliated with JHU are 10% higher. Non-JHU affiliates should send inquiry to Helen Fedor (hfedor@jhmi.edu). Prices are subject to change.
Special Processing (same day biopsy and cell blocks)
Gross, Process, Embed, and  H&E
Unstained Slide
Numbered Serial Sections
Investigator supplied and labelled unstained
Investigator supplied and labelled unstained level section
Plus/Poly/Silane Slide
Chemate Slide
Initial/level/recut H&E
H&E on Supplied Labelled Slide
H&E on Supplied Unstained Section
Additional H&E
Level H&E with Revue
Level H&E on supplied labeled slide
Level Unstained
Additional MAS & AFB
Initial Frozen Section
Additional Frozen Sections
Hourly Rate For Frozen Sectioning
Hourly Rate For Self Cryostat usage*
Cryostat Instruction
Box of "+" slides
Tissue Block Coring for Molecular Studies (up to 5 cores/block)
Tissue Block Coring for Molecular Studies (6-30 cores/block)
Slide Folder
Slide Box 100
Slide Box 25
Slide Mailer
Cardboard Slide Box
Block pickup and return fee
Hourly Rate
Priority Rush
50% upcharge
Standard Rush
20% upcharge

* = Cryostat usage must be cleared by Bonnie Gambichler. All cryostat users must be "checked out" after using the cryostat to confirm it is clean and in appropriate working order. Note - cryostat blades are very sharp!

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  • We no longer offer work request forms here. All requests must go through our campus-wide iLab tool.

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Location: Bond St Annex, Room 305 Basement

For inquiries, please contact:
Bonnie Gambichler
Email: bgambic1@jhmi.edu
Phone 410-502-3358


  • Senior Technician: Bonnie Gambichler, HT
  • Technician: Andre Robinson
  • Technician: Loretha Myers
  • Technician: Wanda Stirling
  • Director: Marc Halushka, MD PhD
  • Manager: Helen Fedor, BS

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Animal Tissue Processing


  • Harvest the tissue and place them in their respective labeled cassettes (use ONLY pencil), place all the cassettes in a large beaker and submerge them in 10% buffered formalin for 48 hours . Cover with 2 layers of foil and place in the hood to avoid fumes or if available use plastic containers with lids.
  • Pour the formalin into an "excess formalin" waste container (found in the hood) and using the same beaker, rinse the blocks in running tap water (cold is fine) for 5 minutes.
  • Drain the tap water and submerge the blocks in 1x PBS and store at 4oC until processing.


Tissues placed in the tissue cassettes should be no thicker than 3-4mm. If placing more than one piece in a cassette they should be of relatively similar size. Do not place 2 organs together in the same cassette that are different sizes - ex . Do not put mouse liver with mouse prostate lobes. If the tumor or organ is thicker than 3-4mm or proportionately larger than other pieces going into the same cassette - slice it into thinner pieces to create tissues with a similar thickness. Some space should remain between the tissue and cassette walls, i.e. it should not be stuffed full . This helps to assure the tissues are processed uniformly.

  • Lymph nodes should always be placed in their own cassette unaccompanied.
  • Colon and small intestines should ALWAYS be flushed out, void of any material prior to fixation and processing. This is to ensure proper fixation and sectioning of the tissue.
  • Contact Bonnie if you have questions or need assistance.

Lens Paper:

Some smaller tissues need to be wrapped in lens paper to assure they will not fall out of the cassette during processing: prostate lobes and lymph nodes (if necessary). There is a special technique to folding the Lens paper -- Please watch our YouTube Videos below or see Bonnie for directions .

Lens paper folding demonstration with a large piece of paper

Lens paper folding demonstration with actual lens paper

Requesting H&E and unstained sections

Following the initial processing of the block, request 1 H&E for each block submitted.

More cuts of each block should only be requested if the initial H&E has been reviewed and the tissue appears well fixed and suitable for the staining or further experimentation. - This helps cut costs, assures that slides and precious tissue do not get wasted and also cuts down on storage of unstained sections in the -20. Some antigens degrade over time so it is best to cut only what you need when you need it.

Do not prebake the slides -- this is to be done as the first step of IHC. This helps to preserve the antigenicity of the tissues.


Blocks: room temperature or 4oC -- avoid heat, direct sunlight and dust.
Unstained sections: -20oC in a Ziploc bag or wrapped in parafilm to avoid condensation.

Tissue Handling Procedures

There is no one size fits all method of tissue preservation to handle all experimental designs. Before harvesting tissue you need to assess your experimental design to best fit the fixation method to the procedure being use to preserve the tissue. Four general procedures exist; snap freezing, OCT media embedding, RNA stabilizing reagent, or fixative. Here are some general guidelines to help give the best quality of tissue preservation and fixation.

  1. Using a sterile blade, bisect the specimen into 0.5 x 0.5 x 0.5 cm or smaller samples. Samples should not exceed 0.5 cm on one dimension, as larger sizes may cause artifacts and cracks in the blocks, Size ranges from 0.5 to 0.3 cm are optimal. The forceps/needle can be used to hold the specimen while bisecting. Avoid crushing artifacts by gently but firmly securing the specimen with the needle/forceps while cutting.
  2. In order to minimize changes secondary to autolysis, specimens must be placed on ice and/or processed as quickly as possible after resection. Ideally, specimens should be snap frozen or placed in appropriate reagent within 5 minutes from loss of vascularization
  3. After cutting tissue from each anatomic site to the appropriate size, specimens are placed into separate sterile labeled vials or containers for snap freezing, OCT media embedding, RNA stabilizing reagent, or fixative.
    • Flash freezing in liquid nitrogen
    • Formalin fixation
    • OCT embedded sample
    • RNA stabilizing reagent

  1. Flash freezing in liquid nitrogen provides excellent specimen integrity and a wide array of options for tissue analysis. Snap-freezing rather than slowly freezing reduces ice crystal formation in tissue. Do not let frozen tissue thaw until after sectioning. The specimen is placed into a sterile 1-2 ml cryo vial, which is then tightly capped and submerged in liquid nitrogen for "flash freezing". The vial is transferred from the temporary LN2 transport container to a liquid nitrogen storage tank for long-term storage.
    To Freeze Tissue: Liquid nitrogen/ Cryo vial method
    • Label tube (1.8 to 2 ml)
    • Cut tissue
    • Put in tube
    • Screw on lid
    • Plunge in liquid nitrogen.
  2. Formalin Fixation is used to stabilize protein in fresh tissue, and prevent autolysis and putrefaction. Fresh tissue specimens which have been fixed in 10% buffered formalin and embedded in paraffin blocks can be sectioned, and stained with Hematoxylin and Eosin (H&E). It is not possible to prepare high quality H&E sections from snap frozen sections; hence Formalin fixed Paraffin embedded tissue (FFPE) provides the best morphological characteristics of tissue, and FFPE sections can be used for immunohistochemical analyses of protein expression.
    • Prior to the procedure, aliquot formalin to specimen containers. The volume of formalin should be a minimum of 15 times the volume of the tissue sample - e.g., 15 ml of formalin per 1 cubic cm of tissue. A 15 ml sterile centrifuge or conical tube can be used, or other capped, leak-proof container.
    • Specimens intended for formalin fixation should be processed after the completion of other fresh tissue procedures, such as flash freezing, embedding in OCT compound, and submersion in RNA stabilizing reagent.
    • The tissue sample should be trimmed such that it is approximately 0.4 cm in thickness. Specimens that exceed this dimension may not allow for adequate perfusion of the formalin.
    • The tissue should be fixed at room temperature for a minimum of 24 to 48 hours, at which point the tissue can be transferred to a histology lab for processing and embedding in paraffin.
  3. Embedding in OCT compound followed by flash freezing not only preserves DNA, RNA, and protein integrity, but also allows for sectioning of the frozen tissue. Removal of excess liquid prior to freezing will prevent fracturing during sectioning. Rinsing any excess blood/liquids with saline or PBS followed by absorption with Kim-wipe, gauze or paper can make a dramatic difference in the time consuming sectioning process later on and only takes a few more seconds.

    For this method place a drop of OCT into a small plastic tray, cryo mold or weigh boat, the tissue sample is placed in the drop and oriented. If orientation is important, special care should be taken to insure that the surface touching the face of the mold is placed properly, as this will be the side that will produce sections. The plastic tray is held with a forceps over the mouth of the liquid nitrogen transport vessel for freezing. As it begins to freeze pour more OCT onto the specimen until it is completely covered and continue to hold the tray in the vapor phase of nitrogen. Fill each cryomold with OCT by slowly and carefully filling the mold to the top. It is important to avoid formation of air bubbles, and to ensure that the top surface of the OCT compound is completely level. Avoid any uneven surfaces. After hardening of the OCT compound, the tray is placed in a pr-labeled bag or vial and transferred to a liquid nitrogen storage tank or -80 C freezer for storage.

    If orientation is not important, use a sterile forceps or needle, transfer the specimen to an OCT-filled cryomold and gently submerge the tissue in the OCT until it is completely covered. None of the tissue should remain exposed. Letting this settle for 30 sec to allow the OCT to wet surface of the tissue.

    • The OCT can be hardened by holding the cryomold with a forceps over the opening of the liquid nitrogen transfer container. Freezer gloves and a face shield should be used during the procedure. Alternatively, the molds may be placed on grate that has been placed over the opening of the LN2 container for hardening. After the OCT has hardened (about one minute), place the mold into a pre-labeled specimen bag or vial and from this point over should never be allowed to warm up.
    • Another method is to float out a metal pan (like the ones you sterilize surgical tools in) on a liquid nitrogen bath (in a Styrofoam container or large Dewar). Place fresh or cryoprotected tissue into cryomold with OCT in it, and add sufficient OCT to insure the tissue is completely covered. Place mold onto metal tray and close lid of Dewar or Styrofoam container. Let freeze. When frozen wrap in foil and place into a biopsy bag, place into -80 deg C for long-term storage.
    • Freezing tissue on Dry Ice or in the freezer is not recommended. These methods cause freezing artifacts, and desiccation of the tissue.
    • Freezing tissue too quickly by submersing into the Liquid Nitrogen will cause the blocks to crack which makes them very difficult or impossible to section. This happens because the outside tissue begins to freeze more quickly than internal portion.
  4. RNA stabilizing agent, as specific and non-specific RNA degradation begins immediately after tissue harvest, prompt transfer of fresh specimens into an RNA stabilizing reagent is helpful to minimize changes in gene expression, and ensure accurate quantitative analysis of gene expression. This protocol is intended for use with RNA later, but similar products (RNAzol, Trizol) are widely used. Frozen specimens are not appropriate for use with this protocol.
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